An introduction to Mechanism design: Single Item...
Transcript of An introduction to Mechanism design: Single Item...
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
An introduction to Mechanism design:Single Item Auctions
Maria Serna
Fall 2017
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
1 Mechanism design
2 Auctions:Context and Definitions
3 Single item auctions
4 Analyzing auctions
5 Revenue in auctions
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Mechanism design
Players have hidden information and try to manipulate theworld
Mediator wants to avoid some type of social misbehavior
An example: resource sharing
How to split a pizza among two kids so that they do not envyeach other?
mediator has to design an algorithm (mechanism) to split thepizza and to allocate the two pieces.Ask one kid to split the pizza and let the other choose theportion
This mechanism provides an envy-free splitting
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Mechanism design
Players have hidden information and try to manipulate theworld
Mediator wants to avoid some type of social misbehavior
An example: resource sharing
How to split a pizza among two kids so that they do not envyeach other?
mediator has to design an algorithm (mechanism) to split thepizza and to allocate the two pieces.Ask one kid to split the pizza and let the other choose theportion
This mechanism provides an envy-free splitting
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Mechanism design
Players have hidden information and try to manipulate theworld
Mediator wants to avoid some type of social misbehavior
An example: resource sharing
How to split a pizza among two kids so that they do not envyeach other?
mediator has to design an algorithm (mechanism) to split thepizza and to allocate the two pieces.
Ask one kid to split the pizza and let the other choose theportion
This mechanism provides an envy-free splitting
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Mechanism design
Players have hidden information and try to manipulate theworld
Mediator wants to avoid some type of social misbehavior
An example: resource sharing
How to split a pizza among two kids so that they do not envyeach other?
mediator has to design an algorithm (mechanism) to split thepizza and to allocate the two pieces.Ask one kid to split the pizza and let the other choose theportion
This mechanism provides an envy-free splitting
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Mechanism design
Players have hidden information and try to manipulate theworld
Mediator wants to avoid some type of social misbehavior
An example: resource sharing
How to split a pizza among two kids so that they do not envyeach other?
mediator has to design an algorithm (mechanism) to split thepizza and to allocate the two pieces.Ask one kid to split the pizza and let the other choose theportion
This mechanism provides an envy-free splitting
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Mechanism design
One way to design mechanism combines prizing withallocations.
We will focus on the study of some auctions:How to sell items to potential buyers with private valuations.
Objective: truth-telling
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Mechanism design
One way to design mechanism combines prizing withallocations.
We will focus on the study of some auctions:How to sell items to potential buyers with private valuations.
Objective: truth-telling
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Mechanism design
One way to design mechanism combines prizing withallocations.
We will focus on the study of some auctions:How to sell items to potential buyers with private valuations.
Objective: truth-telling
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Mechanism design
One way to design mechanism combines prizing withallocations.
We will focus on the study of some auctions:How to sell items to potential buyers with private valuations.
Objective: truth-telling
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
1 Mechanism design
2 Auctions:Context and Definitions
3 Single item auctions
4 Analyzing auctions
5 Revenue in auctions
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
Prices
What is the right price for objects?
The government wants to sell a big building.
Buyer 1: willing to pay 200 Billion.Buyer 2: willing to pay 100 Billion.Buyer 3: does not need the building, but wants to buy it if hecan resale it with a profit.
But, all those values are private, known only by the buyer.
how to get the building worth?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
Prices
What is the right price for objects?
The government wants to sell a big building.
Buyer 1: willing to pay 200 Billion.Buyer 2: willing to pay 100 Billion.Buyer 3: does not need the building, but wants to buy it if hecan resale it with a profit.
But, all those values are private, known only by the buyer.
how to get the building worth?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
Prices
What is the right price for objects?
The government wants to sell a big building.
Buyer 1: willing to pay 200 Billion.Buyer 2: willing to pay 100 Billion.Buyer 3: does not need the building, but wants to buy it if hecan resale it with a profit.
But, all those values are private, known only by the buyer.
how to get the building worth?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
Prices
What is the right price for objects?
The government wants to sell a big building.
Buyer 1: willing to pay 200 Billion.Buyer 2: willing to pay 100 Billion.Buyer 3: does not need the building, but wants to buy it if hecan resale it with a profit.
But, all those values are private, known only by the buyer.
how to get the building worth?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
Prices
What is the right price for objects?
The government wants to sell a big building.
Buyer 1: willing to pay 200 Billion.Buyer 2: willing to pay 100 Billion.Buyer 3: does not need the building, but wants to buy it if hecan resale it with a profit.
But, all those values are private, known only by the buyer.
how to get the building worth?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
Prices
Even when the true preferences of the buyers are knownit is not clear how to price the objects and how to allocatethem.
Buyers might lie and manipulate to get better prices and/orbetter allocation.
How can the true preferences be revealed?
At which cost?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
Prices
Even when the true preferences of the buyers are knownit is not clear how to price the objects and how to allocatethem.
Buyers might lie and manipulate to get better prices and/orbetter allocation.
How can the true preferences be revealed?
At which cost?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
Prices
Even when the true preferences of the buyers are knownit is not clear how to price the objects and how to allocatethem.
Buyers might lie and manipulate to get better prices and/orbetter allocation.
How can the true preferences be revealed?
At which cost?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
Prices
Even when the true preferences of the buyers are knownit is not clear how to price the objects and how to allocatethem.
Buyers might lie and manipulate to get better prices and/orbetter allocation.
How can the true preferences be revealed?
At which cost?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
Auction theory
Auction theory is a sub-field of Mechanism Design.
Aim: Design and analyze the rules and properties of anauction.
Goal: Design an auction so that in equilibrium we get theresults we want.
As in Game theory we rely on rationality.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
Auction theory
Auction theory is a sub-field of Mechanism Design.
Aim: Design and analyze the rules and properties of anauction.
Goal: Design an auction so that in equilibrium we get theresults we want.
As in Game theory we rely on rationality.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
Auction theory
Auction theory is a sub-field of Mechanism Design.
Aim: Design and analyze the rules and properties of anauction.
Goal:
Design an auction so that in equilibrium we get theresults we want.
As in Game theory we rely on rationality.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
Auction theory
Auction theory is a sub-field of Mechanism Design.
Aim: Design and analyze the rules and properties of anauction.
Goal: Design an auction so that in equilibrium we get theresults we want.
As in Game theory we rely on rationality.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
Auction theory
Auction theory is a sub-field of Mechanism Design.
Aim: Design and analyze the rules and properties of anauction.
Goal: Design an auction so that in equilibrium we get theresults we want.
As in Game theory we rely on rationality.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
What is an Auction?
An auction is a mechanism to allocate resources among agroup of bidders.
An auction model includes three major parts:
The set of possible resource allocations.The number (or portion) of goods of each type including legalor other restrictions on how the goods may be allocated.Rules for bidding and clearing.A procedure to determine who wins what (allocation) and howmuch pays (payment) on the basis of the received information.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
What is an Auction?
An auction is a mechanism to allocate resources among agroup of bidders.
An auction model includes three major parts:
The set of possible resource allocations.The number (or portion) of goods of each type including legalor other restrictions on how the goods may be allocated.Rules for bidding and clearing.A procedure to determine who wins what (allocation) and howmuch pays (payment) on the basis of the received information.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
What is an Auction?
An auction is a mechanism to allocate resources among agroup of bidders.
An auction model includes three major parts:
The set of possible resource allocations.The number (or portion) of goods of each type including legalor other restrictions on how the goods may be allocated.Rules for bidding and clearing.A procedure to determine who wins what (allocation) and howmuch pays (payment) on the basis of the received information.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
What is an Auction?
An auction is a mechanism to allocate resources among agroup of bidders.
An auction model includes three major parts:
The set of possible resource allocations.
The number (or portion) of goods of each type including legalor other restrictions on how the goods may be allocated.Rules for bidding and clearing.A procedure to determine who wins what (allocation) and howmuch pays (payment) on the basis of the received information.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
What is an Auction?
An auction is a mechanism to allocate resources among agroup of bidders.
An auction model includes three major parts:
The set of possible resource allocations.The number (or portion) of goods of each type including legalor other restrictions on how the goods may be allocated.
Rules for bidding and clearing.A procedure to determine who wins what (allocation) and howmuch pays (payment) on the basis of the received information.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
What is an Auction?
An auction is a mechanism to allocate resources among agroup of bidders.
An auction model includes three major parts:
The set of possible resource allocations.The number (or portion) of goods of each type including legalor other restrictions on how the goods may be allocated.Rules for bidding and clearing.
A procedure to determine who wins what (allocation) and howmuch pays (payment) on the basis of the received information.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
What is an Auction?
An auction is a mechanism to allocate resources among agroup of bidders.
An auction model includes three major parts:
The set of possible resource allocations.The number (or portion) of goods of each type including legalor other restrictions on how the goods may be allocated.Rules for bidding and clearing.A procedure to determine who wins what (allocation) and howmuch pays (payment) on the basis of the received information.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
Strategic component?
Bidders decide the information that is revealed in theinteraction.
When?
What?
To whom?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
Strategic component?
Bidders decide the information that is revealed in theinteraction.
When?
What?
To whom?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
PricesAuctions
Strategic component?
Bidders decide the information that is revealed in theinteraction.
When?
What?
To whom?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
1 Mechanism design
2 Auctions:Context and Definitions
3 Single item auctions
4 Analyzing auctions
5 Revenue in auctions
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
Single item auctions
For today’s lecture assume that we have a single item or good tosell.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
Open auction
The auctioneer and the bidders interact physically.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
English Auction
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
English Auction
The auctioneer starts the bidding at some reservation price.
The bidders then shout out ascending prices.
Once bidders stop shouting, the highest bidder gets the goodat the declared price.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
English Auction
The auctioneer starts the bidding at some reservation price.
The bidders then shout out ascending prices.
Once bidders stop shouting, the highest bidder gets the goodat the declared price.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
English Auction
The auctioneer starts the bidding at some reservation price.
The bidders then shout out ascending prices.
Once bidders stop shouting, the highest bidder gets the goodat the declared price.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
English Auction
The auctioneer starts the bidding at some reservation price.
The bidders then shout out ascending prices.
Once bidders stop shouting, the highest bidder gets the goodat the declared price.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
Japanese Auction
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
Japanese Auction
The auctioneer calls out ascending prices.
All bidders start out standing, when the price reaches a levelthat a bidder is not willing to pay, that bidder sits down.
Once a bidder sits down, they can’t get back up
The only action that a bidder may take is to drop out of theauction
The last person standing gets the good at the last priceshouted.
analytically more tractable than English because jump biddingcan’t occur.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
Japanese Auction
The auctioneer calls out ascending prices.
All bidders start out standing, when the price reaches a levelthat a bidder is not willing to pay, that bidder sits down.
Once a bidder sits down, they can’t get back up
The only action that a bidder may take is to drop out of theauction
The last person standing gets the good at the last priceshouted.
analytically more tractable than English because jump biddingcan’t occur.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
Japanese Auction
The auctioneer calls out ascending prices.
All bidders start out standing, when the price reaches a levelthat a bidder is not willing to pay, that bidder sits down.
Once a bidder sits down, they can’t get back up
The only action that a bidder may take is to drop out of theauction
The last person standing gets the good at the last priceshouted.
analytically more tractable than English because jump biddingcan’t occur.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
Japanese Auction
The auctioneer calls out ascending prices.
All bidders start out standing, when the price reaches a levelthat a bidder is not willing to pay, that bidder sits down.
Once a bidder sits down, they can’t get back up
The only action that a bidder may take is to drop out of theauction
The last person standing gets the good at the last priceshouted.
analytically more tractable than English because jump biddingcan’t occur.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
Japanese Auction
The auctioneer calls out ascending prices.
All bidders start out standing, when the price reaches a levelthat a bidder is not willing to pay, that bidder sits down.
Once a bidder sits down, they can’t get back up
The only action that a bidder may take is to drop out of theauction
The last person standing gets the good at the last priceshouted.
analytically more tractable than English because jump biddingcan’t occur.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
Japanese Auction
The auctioneer calls out ascending prices.
All bidders start out standing, when the price reaches a levelthat a bidder is not willing to pay, that bidder sits down.
Once a bidder sits down, they can’t get back up
The only action that a bidder may take is to drop out of theauction
The last person standing gets the good at the last priceshouted.
analytically more tractable than English because jump biddingcan’t occur.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
Japanese Auction
The auctioneer calls out ascending prices.
All bidders start out standing, when the price reaches a levelthat a bidder is not willing to pay, that bidder sits down.
Once a bidder sits down, they can’t get back up
The only action that a bidder may take is to drop out of theauction
The last person standing gets the good at the last priceshouted.
analytically more tractable than English because jump biddingcan’t occur.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
Dutch Auction
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
Dutch Auction
The auctioneer starts a clock at some high value; it descends
At some point, a bidder shouts mine! and gets the good atthe price shown on the clock.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
Dutch Auction
The auctioneer starts a clock at some high value; it descends
At some point, a bidder shouts mine! and gets the good atthe price shown on the clock.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
Dutch Auction
The auctioneer starts a clock at some high value; it descends
At some point, a bidder shouts mine! and gets the good atthe price shown on the clock.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
Sealed-Bid auctions
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
Sealed bid auctions
The auctioneer and the bidders do not interact physically.
The bidders submit their bid privately to the auctioneer.
The bidder on the basis of the bid sets allocation and price.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
First price (FP) Auction
The bidders write down a price and send it to the auctioneer.
The auctioneer awards the good to the bidder with thehighest bid.
The winner pays the amount of his bid.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
First price (FP) Auction
The bidders write down a price and send it to the auctioneer.
The auctioneer awards the good to the bidder with thehighest bid.
The winner pays the amount of his bid.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
First price (FP) Auction
The bidders write down a price and send it to the auctioneer.
The auctioneer awards the good to the bidder with thehighest bid.
The winner pays the amount of his bid.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
First price (FP) Auction
The bidders write down a price and send it to the auctioneer.
The auctioneer awards the good to the bidder with thehighest bid.
The winner pays the amount of his bid.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
Second price (SP) Auction
The bidders write down a price and send it to the auctioneer.
The auctioneer awards the good to the bidder with thehighest bid.
The winner pays the amount bid by the second-highest bidder.
Second price auctions are also known as Vickrey auctions.defined by William Vickrey in 1961. Vickrey won the Nobelprize in Economics in 1996.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
Second price (SP) Auction
The bidders write down a price and send it to the auctioneer.
The auctioneer awards the good to the bidder with thehighest bid.
The winner pays the amount bid by the second-highest bidder.
Second price auctions are also known as Vickrey auctions.defined by William Vickrey in 1961. Vickrey won the Nobelprize in Economics in 1996.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
Second price (SP) Auction
The bidders write down a price and send it to the auctioneer.
The auctioneer awards the good to the bidder with thehighest bid.
The winner pays the amount bid by the second-highest bidder.
Second price auctions are also known as Vickrey auctions.defined by William Vickrey in 1961. Vickrey won the Nobelprize in Economics in 1996.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
Second price (SP) Auction
The bidders write down a price and send it to the auctioneer.
The auctioneer awards the good to the bidder with thehighest bid.
The winner pays the amount bid by the second-highest bidder.
Second price auctions are also known as Vickrey auctions.defined by William Vickrey in 1961. Vickrey won the Nobelprize in Economics in 1996.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
Second price (SP) Auction
The bidders write down a price and send it to the auctioneer.
The auctioneer awards the good to the bidder with thehighest bid.
The winner pays the amount bid by the second-highest bidder.
Second price auctions are also known as Vickrey auctions.defined by William Vickrey in 1961. Vickrey won the Nobelprize in Economics in 1996.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
All-Pay Auction
The bidders write down a price and send it to the auctioneer.
The auctioneer awards the good to the bidder with thehighest bid.
Everyone pays the amount of their bid regardless of whetheror not they get the good.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
All-Pay Auction
The bidders write down a price and send it to the auctioneer.
The auctioneer awards the good to the bidder with thehighest bid.
Everyone pays the amount of their bid regardless of whetheror not they get the good.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
All-Pay Auction
The bidders write down a price and send it to the auctioneer.
The auctioneer awards the good to the bidder with thehighest bid.
Everyone pays the amount of their bid regardless of whetheror not they get the good.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Open auctionsSealed-Bid auctions
All-Pay Auction
The bidders write down a price and send it to the auctioneer.
The auctioneer awards the good to the bidder with thehighest bid.
Everyone pays the amount of their bid regardless of whetheror not they get the good.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
1 Mechanism design
2 Auctions:Context and Definitions
3 Single item auctions
4 Analyzing auctions
5 Revenue in auctions
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
Auctioneer goals
A seller (“auctioneer”) may have several goals.
Revenue: maximize profit.
Efficiency: maximize social welfare:Give the item to the buyer that wants it the most. (regardlessof payments.)
Fairness:An auction that greedily maximizes the total utility of all users(i.e., the social welfare) in each round could lead to a subsetof secondary users starving for products.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
Auctioneer goals
A seller (“auctioneer”) may have several goals.
Revenue: maximize profit.
Efficiency: maximize social welfare:
Give the item to the buyer that wants it the most. (regardlessof payments.)
Fairness:An auction that greedily maximizes the total utility of all users(i.e., the social welfare) in each round could lead to a subsetof secondary users starving for products.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
Auctioneer goals
A seller (“auctioneer”) may have several goals.
Revenue: maximize profit.
Efficiency: maximize social welfare:Give the item to the buyer that wants it the most. (regardlessof payments.)
Fairness:An auction that greedily maximizes the total utility of all users(i.e., the social welfare) in each round could lead to a subsetof secondary users starving for products.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
Auctioneer goals
A seller (“auctioneer”) may have several goals.
Revenue: maximize profit.
Efficiency: maximize social welfare:Give the item to the buyer that wants it the most. (regardlessof payments.)
Fairness:An auction that greedily maximizes the total utility of all users(i.e., the social welfare) in each round could lead to a subsetof secondary users starving for products.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
Bidder goal
Auctions are used precisely because the seller is unsure aboutthe values that bidders attach to the object being sold.
A valuation is the maximum amount each bidder is willing topay.
If each bidder knows the value of the object to himself at thetime of bidding, the situation is called one of private values.
If the object has a value and the players have some believe onsuch value, the situation is called one of common values.
A bidder wants to get the object as cheap as possible.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
Bidder goal
Auctions are used precisely because the seller is unsure aboutthe values that bidders attach to the object being sold.
A valuation is the maximum amount each bidder is willing topay.
If each bidder knows the value of the object to himself at thetime of bidding, the situation is called one of private values.
If the object has a value and the players have some believe onsuch value, the situation is called one of common values.
A bidder wants to get the object as cheap as possible.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
Bidder goal
Auctions are used precisely because the seller is unsure aboutthe values that bidders attach to the object being sold.
A valuation is the maximum amount each bidder is willing topay.
If each bidder knows the value of the object to himself at thetime of bidding, the situation is called one of private values.
If the object has a value and the players have some believe onsuch value, the situation is called one of common values.
A bidder wants to get the object as cheap as possible.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
Bidder goal
Auctions are used precisely because the seller is unsure aboutthe values that bidders attach to the object being sold.
A valuation is the maximum amount each bidder is willing topay.
If each bidder knows the value of the object to himself at thetime of bidding, the situation is called one of private values.
If the object has a value and the players have some believe onsuch value, the situation is called one of common values.
A bidder wants to get the object as cheap as possible.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
Strategic equivalence
Definition
Two games with the same set of players and the same strategyspace are said to be strategically equivalent if each player’sexpected profits under one of the games are identical to hisexpected profits in the other game.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auctions: strategic equivalences
Lemma
SP-auctions are equivalent to Japanese auctions.
Given that bidders bid truthfully, the outcomes in the twoauctions are the same.
Actually, in Japanese auctions bidders observe additionalinformation: valuations of other players.
This might create a herd phenomena.
But do bidders bid truthfully in SP-auctions?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auctions: strategic equivalences
Lemma
SP-auctions are equivalent to Japanese auctions.
Given that bidders bid truthfully, the outcomes in the twoauctions are the same.
Actually, in Japanese auctions bidders observe additionalinformation: valuations of other players.
This might create a herd phenomena.
But do bidders bid truthfully in SP-auctions?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auctions: strategic equivalences
Lemma
SP-auctions are equivalent to Japanese auctions.
Given that bidders bid truthfully, the outcomes in the twoauctions are the same.
Actually, in Japanese auctions bidders observe additionalinformation: valuations of other players.
This might create a herd phenomena.
But do bidders bid truthfully in SP-auctions?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auction: Modeling
n bidders
Each bidder has value vi for the item willingness to pay.Known only to him – private value.
If Bidder i wins and pays pi , his utility is vi–pi .Her utility is 0 when she loses.
Bidders prefer losing than paying more than their value.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auction: Modeling
n bidders
Each bidder has value vi for the item willingness to pay.Known only to him – private value.
If Bidder i wins and pays pi , his utility is vi–pi .Her utility is 0 when she loses.
Bidders prefer losing than paying more than their value.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auction: Strategies
A strategy for each bidder:
how to bid given your value?
Examples for strategies:
bi (vi ) = vi truthful!bi (vi ) = vi/2bi (vi ) = vi/n if you have information on the number of bidders.If vi < 50, bi (vi ) = vi ; otherwise, bi (vi ) = vi + 17.
The auction is a strategic game, where these strategies arethe pure strategies (infinitely many).
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auction: Strategies
A strategy for each bidder:
how to bid given your value?
Examples for strategies:
bi (vi ) = vi truthful!bi (vi ) = vi/2bi (vi ) = vi/n if you have information on the number of bidders.If vi < 50, bi (vi ) = vi ; otherwise, bi (vi ) = vi + 17.
The auction is a strategic game, where these strategies arethe pure strategies (infinitely many).
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auction: Strategies
A strategy for each bidder:
how to bid given your value?
Examples for strategies:
bi (vi ) = vi truthful!bi (vi ) = vi/2bi (vi ) = vi/n if you have information on the number of bidders.If vi < 50, bi (vi ) = vi ; otherwise, bi (vi ) = vi + 17.
The auction is a strategic game, where these strategies arethe pure strategies (infinitely many).
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auction: Strategies
A strategy for each bidder:
how to bid given your value?
Examples for strategies:
bi (vi ) = vi truthful!bi (vi ) = vi/2bi (vi ) = vi/n if you have information on the number of bidders.If vi < 50, bi (vi ) = vi ; otherwise, bi (vi ) = vi + 17.
The auction is a strategic game, where these strategies arethe pure strategies (infinitely many).
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auction: Strategies
A strategy for each bidder:
how to bid given your value?
Examples for strategies:
bi (vi ) = vi truthful!bi (vi ) = vi/2bi (vi ) = vi/n if you have information on the number of bidders.If vi < 50, bi (vi ) = vi ; otherwise, bi (vi ) = vi + 17.
The auction is a strategic game, where these strategies arethe pure strategies (infinitely many).
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auctions: Equilibrium behaviour
Theorem
In SP-price auctions truth-telling is a dominant strategy.
In Japanese auctions with private values too.
Let’s prove now that truthfulness is a dominant strategy.
The proof is by case analysis.
We have to show that Bidder 1 will never benefit from biddinga bid that is not v1.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auctions: Equilibrium behaviour
Theorem
In SP-price auctions truth-telling is a dominant strategy.
In Japanese auctions with private values too.
Let’s prove now that truthfulness is a dominant strategy.
The proof is by case analysis.
We have to show that Bidder 1 will never benefit from biddinga bid that is not v1.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auctions: Equilibrium behaviour
Case 1: Bidder 1 wins when bidding v1.
v1 is the highest bid and b2 is the 2nd highest.
Bidder 1 utility is v1 − b2 > 0.
Bidding above b2 will not change anything.
Bidding less than b2 will turn him into a loser. From positiveutility to zero!
No gain from lying!.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auctions: Equilibrium behaviour
Case 1: Bidder 1 wins when bidding v1.
v1 is the highest bid and b2 is the 2nd highest.
Bidder 1 utility is v1 − b2 > 0.
Bidding above b2 will not change anything.
Bidding less than b2 will turn him into a loser. From positiveutility to zero!
No gain from lying!.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auctions: Equilibrium behaviour
Case 1: Bidder 1 wins when bidding v1.
v1 is the highest bid and b2 is the 2nd highest.
Bidder 1 utility is v1 − b2 > 0.
Bidding above b2 will not change anything.
Bidding less than b2 will turn him into a loser. From positiveutility to zero!
No gain from lying!.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auctions: Equilibrium behaviour
Case 1: Bidder 1 wins when bidding v1.
v1 is the highest bid and b2 is the 2nd highest.
Bidder 1 utility is v1 − b2 > 0.
Bidding above b2 will not change anything.
Bidding less than b2 will turn him into a loser. From positiveutility to zero!
No gain from lying!.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auctions: Equilibrium behaviour
Case 2: Bidder 1 loses when bidding v1.
Let b2 be the 2nd highest bid now.
Bidder 1 utility is 0.
Any bid below b2 will gain him zero utility.
Any bid above b2 will gain him either 0 (still not wining)or an utility smaller that v1 − b2 < 0 (losing is better).
Again, no gain from lying!.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auctions: Equilibrium behaviour
Case 2: Bidder 1 loses when bidding v1.
Let b2 be the 2nd highest bid now.
Bidder 1 utility is 0.
Any bid below b2 will gain him zero utility.
Any bid above b2 will gain him either 0 (still not wining)or an utility smaller that v1 − b2 < 0 (losing is better).
Again, no gain from lying!.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auctions: Equilibrium behaviour
Case 2: Bidder 1 loses when bidding v1.
Let b2 be the 2nd highest bid now.
Bidder 1 utility is 0.
Any bid below b2 will gain him zero utility.
Any bid above b2 will gain him either 0 (still not wining)or an utility smaller that v1 − b2 < 0 (losing is better).
Again, no gain from lying!.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auctions: Equilibrium behaviour
Case 2: Bidder 1 loses when bidding v1.
Let b2 be the 2nd highest bid now.
Bidder 1 utility is 0.
Any bid below b2 will gain him zero utility.
Any bid above b2 will gain him either 0 (still not wining)or an utility smaller that v1 − b2 < 0 (losing is better).
Again, no gain from lying!.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auctions: Efficiency
Since SP-auction is truthful, we can conclude it is efficient.
That is, in equilibrium,
the auctioneer allocates the item tothe bidder with the highest value.
With the actual highest value, not just the highest bid.Without assuming anything on the values.
However the seller does not get maximum revenue.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auctions: Efficiency
Since SP-auction is truthful, we can conclude it is efficient.
That is, in equilibrium, the auctioneer allocates the item tothe bidder with the highest value.
With the actual highest value, not just the highest bid.Without assuming anything on the values.
However the seller does not get maximum revenue.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
SP-Auctions: Efficiency
Since SP-auction is truthful, we can conclude it is efficient.
That is, in equilibrium, the auctioneer allocates the item tothe bidder with the highest value.
With the actual highest value, not just the highest bid.Without assuming anything on the values.
However the seller does not get maximum revenue.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP-Auctions Strategic equivalences
Lemma
FP-price auctions are strategically equivalent to Dutch auctions.
Strategies:
FP: Given that no one has a higher bid,what is the maximum I am willing to pay?
Dutch: Given that no body has raised their hand,when should I raise mine?No new information is revealed during the auction!
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP-Auctions Strategic equivalences
Lemma
FP-price auctions are strategically equivalent to Dutch auctions.
Strategies:
FP: Given that no one has a higher bid,what is the maximum I am willing to pay?
Dutch: Given that no body has raised their hand,when should I raise mine?
No new information is revealed during the auction!
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP-Auctions Strategic equivalences
Lemma
FP-price auctions are strategically equivalent to Dutch auctions.
Strategies:
FP: Given that no one has a higher bid,what is the maximum I am willing to pay?
Dutch: Given that no body has raised their hand,when should I raise mine?No new information is revealed during the auction!
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP-Auctions: properties
FP and Dutch auctions are
Equivalent.
Efficient?Yes, in equilibrium the good will be allocated to the playerwith a higher valuation.
Truthful?v1 = 100 and other’s highest bid b2 = 30.Player 1 by bidding 31 gets the good and a positive benefit.No truthfulness in the strategic setting.We continue the analysis on Bayesian games.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP-Auctions: properties
FP and Dutch auctions are
Equivalent.
Efficient?Yes, in equilibrium the good will be allocated to the playerwith a higher valuation.
Truthful?
v1 = 100 and other’s highest bid b2 = 30.Player 1 by bidding 31 gets the good and a positive benefit.No truthfulness in the strategic setting.We continue the analysis on Bayesian games.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP-Auctions: properties
FP and Dutch auctions are
Equivalent.
Efficient?Yes, in equilibrium the good will be allocated to the playerwith a higher valuation.
Truthful?v1 = 100 and other’s highest bid b2 = 30.
Player 1 by bidding 31 gets the good and a positive benefit.No truthfulness in the strategic setting.We continue the analysis on Bayesian games.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP-Auctions: properties
FP and Dutch auctions are
Equivalent.
Efficient?Yes, in equilibrium the good will be allocated to the playerwith a higher valuation.
Truthful?v1 = 100 and other’s highest bid b2 = 30.Player 1 by bidding 31
gets the good and a positive benefit.No truthfulness in the strategic setting.We continue the analysis on Bayesian games.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP-Auctions: properties
FP and Dutch auctions are
Equivalent.
Efficient?Yes, in equilibrium the good will be allocated to the playerwith a higher valuation.
Truthful?v1 = 100 and other’s highest bid b2 = 30.Player 1 by bidding 31 gets the good and a positive benefit.
No truthfulness in the strategic setting.We continue the analysis on Bayesian games.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP-Auctions: properties
FP and Dutch auctions are
Equivalent.
Efficient?Yes, in equilibrium the good will be allocated to the playerwith a higher valuation.
Truthful?v1 = 100 and other’s highest bid b2 = 30.Player 1 by bidding 31 gets the good and a positive benefit.No truthfulness in the strategic setting.
We continue the analysis on Bayesian games.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP-Auctions: properties
FP and Dutch auctions are
Equivalent.
Efficient?Yes, in equilibrium the good will be allocated to the playerwith a higher valuation.
Truthful?v1 = 100 and other’s highest bid b2 = 30.Player 1 by bidding 31 gets the good and a positive benefit.No truthfulness in the strategic setting.We continue the analysis on Bayesian games.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP auctions: Bayesian analysis
How do people behave?
They have beliefs on the valuations of the other players!
As usual beliefs are modeled with probability distributions.
Bidders do not know their opponent’s values, i.e., there isincomplete information.Each bidder’s strategy must maximize her expected payoffaccounting for the uncertainty about opponent values.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP auctions: Bayesian analysis
How do people behave?
They have beliefs on the valuations of the other players!
As usual beliefs are modeled with probability distributions.
Bidders do not know their opponent’s values, i.e., there isincomplete information.Each bidder’s strategy must maximize her expected payoffaccounting for the uncertainty about opponent values.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP auctions: Bayesian analysis
How do people behave?
They have beliefs on the valuations of the other players!
As usual beliefs are modeled with probability distributions.
Bidders do not know their opponent’s values, i.e., there isincomplete information.Each bidder’s strategy must maximize her expected payoffaccounting for the uncertainty about opponent values.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP auctions: Bayesian analysis
How do people behave?
They have beliefs on the valuations of the other players!
As usual beliefs are modeled with probability distributions.
Bidders do not know their opponent’s values, i.e., there isincomplete information.Each bidder’s strategy must maximize her expected payoffaccounting for the uncertainty about opponent values.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP auctions: Bayesian analysis
How do people behave?
They have beliefs on the valuations of the other players!
As usual beliefs are modeled with probability distributions.
Bidders do not know their opponent’s values, i.e., there isincomplete information.
Each bidder’s strategy must maximize her expected payoffaccounting for the uncertainty about opponent values.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP auctions: Bayesian analysis
How do people behave?
They have beliefs on the valuations of the other players!
As usual beliefs are modeled with probability distributions.
Bidders do not know their opponent’s values, i.e., there isincomplete information.Each bidder’s strategy must maximize her expected payoffaccounting for the uncertainty about opponent values.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
Auctions with uniform distributions
A simple Bayesian auction model:
2 buyersValues are between 0 and 1.Values are distributed uniformly on [0, 1]
What is the equilibrium in this game of incompleteinformation?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
Auctions with uniform distributions
A simple Bayesian auction model:
2 buyersValues are between 0 and 1.Values are distributed uniformly on [0, 1]
What is the equilibrium in this game of incompleteinformation?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
Auctions with uniform distributions
A simple Bayesian auction model:
2 buyersValues are between 0 and 1.Values are distributed uniformly on [0, 1]
What is the equilibrium in this game of incompleteinformation?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
Auctions with uniform distributions
A simple Bayesian auction model:
2 buyersValues are between 0 and 1.Values are distributed uniformly on [0, 1]
What is the equilibrium in this game of incompleteinformation?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
Simple FP: Equilibrium
2 bidders uniform distributionBidding b(v) = v/2 is an equilibrium
Assume that Bidder 2’s strategy is b2(v) = v2/2.
Let us show that b1(v) = v1/2 is a best response to Bidder 2.(clearly, no need to bid above v1).
Bidder 1’s utility is:
Prob[b1 > b2] (v1 − b1) =
=Prob[b1 > v2/2] (v1 − b1)
=2b1 (v1 − b1)
maximizing for b1 we have: [2b1 (v1 − b1)]′ = 2v1 − 4b1 = 0which gives b1 = v1/2
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
Simple FP: Equilibrium
2 bidders uniform distributionBidding b(v) = v/2 is an equilibrium
Assume that Bidder 2’s strategy is b2(v) = v2/2.
Let us show that b1(v) = v1/2 is a best response to Bidder 2.(clearly, no need to bid above v1).
Bidder 1’s utility is:
Prob[b1 > b2] (v1 − b1) =
=Prob[b1 > v2/2] (v1 − b1)
=2b1 (v1 − b1)
maximizing for b1 we have: [2b1 (v1 − b1)]′ = 2v1 − 4b1 = 0which gives b1 = v1/2
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
Simple FP: Equilibrium
2 bidders uniform distributionBidding b(v) = v/2 is an equilibrium
Assume that Bidder 2’s strategy is b2(v) = v2/2.
Let us show that b1(v) = v1/2 is a best response to Bidder 2.(clearly, no need to bid above v1).
Bidder 1’s utility is:
Prob[b1 > b2] (v1 − b1) =
=Prob[b1 > v2/2] (v1 − b1)
=2b1 (v1 − b1)
maximizing for b1 we have: [2b1 (v1 − b1)]′ = 2v1 − 4b1 = 0which gives b1 = v1/2
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
Simple FP: Equilibrium
2 bidders uniform distributionBidding b(v) = v/2 is an equilibrium
Assume that Bidder 2’s strategy is b2(v) = v2/2.
Let us show that b1(v) = v1/2 is a best response to Bidder 2.(clearly, no need to bid above v1).
Bidder 1’s utility is:
Prob[b1 > b2] (v1 − b1) =
=Prob[b1 > v2/2] (v1 − b1)
=2b1 (v1 − b1)
maximizing for b1 we have: [2b1 (v1 − b1)]′ = 2v1 − 4b1 = 0which gives b1 = v1/2
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
Simple FP: Equilibrium
2 bidders uniform distributionBidding b(v) = v/2 is an equilibrium
Assume that Bidder 2’s strategy is b2(v) = v2/2.
Let us show that b1(v) = v1/2 is a best response to Bidder 2.(clearly, no need to bid above v1).
Bidder 1’s utility is:
Prob[b1 > b2] (v1 − b1) =
=Prob[b1 > v2/2] (v1 − b1)
=2b1 (v1 − b1)
maximizing for b1 we have: [2b1 (v1 − b1)]′ = 2v1 − 4b1 = 0which gives b1 = v1/2
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
Simple FP: Equilibrium
2 bidders uniform distributionBidding b(v) = v/2 is an equilibrium
Assume that Bidder 2’s strategy is b2(v) = v2/2.
Let us show that b1(v) = v1/2 is a best response to Bidder 2.(clearly, no need to bid above v1).
Bidder 1’s utility is:
Prob[b1 > b2] (v1 − b1) =
=Prob[b1 > v2/2] (v1 − b1)
=2b1 (v1 − b1)
maximizing for b1 we have:
[2b1 (v1 − b1)]′ = 2v1 − 4b1 = 0which gives b1 = v1/2
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
Simple FP: Equilibrium
2 bidders uniform distributionBidding b(v) = v/2 is an equilibrium
Assume that Bidder 2’s strategy is b2(v) = v2/2.
Let us show that b1(v) = v1/2 is a best response to Bidder 2.(clearly, no need to bid above v1).
Bidder 1’s utility is:
Prob[b1 > b2] (v1 − b1) =
=Prob[b1 > v2/2] (v1 − b1)
=2b1 (v1 − b1)
maximizing for b1 we have: [2b1 (v1 − b1)]′ = 2v1 − 4b1 = 0which gives b1 = v1/2
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP: uniform values
We consider the simple Bayesian model
n biddersValues drawn uniformly form [0, 1]
Theorem
In a FP auction with n bidders under the uniform values model, thestrategy bi = n−1
n vi , for 1 ≤ i ≤ n, is a Bayesian Nash equilibrium.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP: uniform values
We consider the simple Bayesian model
n biddersValues drawn uniformly form [0, 1]
Theorem
In a FP auction with n bidders under the uniform values model, thestrategy bi = n−1
n vi , for 1 ≤ i ≤ n, is a Bayesian Nash equilibrium.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP: uniform values
We consider the simple Bayesian model
n biddersValues drawn uniformly form [0, 1]
Theorem
In a FP auction with n bidders under the uniform values model, thestrategy bi = n−1
n vi , for 1 ≤ i ≤ n, is a Bayesian Nash equilibrium.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP uniform values: Efficiency
An auction is efficient if, in a Bayesian Nash equilibrium, thebidder with the highest value always wins.
Thus, in the uniform value model FP is efficient.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP uniform values: Efficiency
An auction is efficient if, in a Bayesian Nash equilibrium, thebidder with the highest value always wins.
Thus, in the uniform value model FP is efficient.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
FP uniform values: Efficiency
An auction is efficient if, in a Bayesian Nash equilibrium, thebidder with the highest value always wins.
Thus, in the uniform value model FP is efficient.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
English and Japanese auctions
A much more complicated strategy space than sealed bidauctions
extensive form gamebidders are able to condition their bids on information revealedby othersin the case of English auctions, the ability to place jump bids
Independent private values model (IPV): the n bidders havevalues v1, . . . , vn identically and independently distributedwith cdf F (·).
Theorem
Under the IPV model, it is a dominant strategy for bidders to bidup to (and not beyond) their valuations in both Japanese andEnglish auctions.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
English and Japanese auctions
A much more complicated strategy space than sealed bidauctions
extensive form gamebidders are able to condition their bids on information revealedby othersin the case of English auctions, the ability to place jump bids
Independent private values model (IPV): the n bidders havevalues v1, . . . , vn identically and independently distributedwith cdf F (·).
Theorem
Under the IPV model, it is a dominant strategy for bidders to bidup to (and not beyond) their valuations in both Japanese andEnglish auctions.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
English and Japanese auctions
A much more complicated strategy space than sealed bidauctions
extensive form gamebidders are able to condition their bids on information revealedby othersin the case of English auctions, the ability to place jump bids
Independent private values model (IPV): the n bidders havevalues v1, . . . , vn identically and independently distributedwith cdf F (·).
Theorem
Under the IPV model, it is a dominant strategy for bidders to bidup to (and not beyond) their valuations in both Japanese andEnglish auctions.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
English and Japanese auctions
A much more complicated strategy space than sealed bidauctions
extensive form gamebidders are able to condition their bids on information revealedby othersin the case of English auctions, the ability to place jump bids
Independent private values model (IPV): the n bidders havevalues v1, . . . , vn identically and independently distributedwith cdf F (·).
Theorem
Under the IPV model, it is a dominant strategy for bidders to bidup to (and not beyond) their valuations in both Japanese andEnglish auctions.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
GoalsSP AuctionsFP AuctionsEnglish and Japanese auctions
English and Japanese auctions
A much more complicated strategy space than sealed bidauctions
extensive form gamebidders are able to condition their bids on information revealedby othersin the case of English auctions, the ability to place jump bids
Independent private values model (IPV): the n bidders havevalues v1, . . . , vn identically and independently distributedwith cdf F (·).
Theorem
Under the IPV model, it is a dominant strategy for bidders to bidup to (and not beyond) their valuations in both Japanese andEnglish auctions.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
1 Mechanism design
2 Auctions:Context and Definitions
3 Single item auctions
4 Analyzing auctions
5 Revenue in auctions
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Optimal auctions
Usually the term optimal auctions stands for revenuemaximization.
What is maximal revenue? optimal expected revenue inequilibrium.
Assuming a probability distribution on the values.Over all the possible mechanisms.Under individual-rationality constraints.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Optimal auctions
Usually the term optimal auctions stands for revenuemaximization.
What is maximal revenue? optimal expected revenue inequilibrium.
Assuming a probability distribution on the values.Over all the possible mechanisms.Under individual-rationality constraints.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Optimal auctions
Usually the term optimal auctions stands for revenuemaximization.
What is maximal revenue?
optimal expected revenue inequilibrium.
Assuming a probability distribution on the values.Over all the possible mechanisms.Under individual-rationality constraints.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Optimal auctions
Usually the term optimal auctions stands for revenuemaximization.
What is maximal revenue? optimal expected revenue inequilibrium.
Assuming a probability distribution on the values.Over all the possible mechanisms.Under individual-rationality constraints.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Optimal auctions
Usually the term optimal auctions stands for revenuemaximization.
What is maximal revenue? optimal expected revenue inequilibrium.
Assuming a probability distribution on the values.Over all the possible mechanisms.Under individual-rationality constraints.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Simple auctions with uniform distributions
We consider the simple Bayesian model
2 biddersValues drawn uniformly form [0, 1] x , y
What is the expected revenue gained by SP and FP auctions?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Simple auctions with uniform distributions
We consider the simple Bayesian model
2 biddersValues drawn uniformly form [0, 1] x , y
What is the expected revenue gained by SP and FP auctions?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue in SP Simple auctions with uniform distributions
In a SP auction, the payment is the minimum of the twovalues.
E [revenue] = E [min{x , y}]
Claim: When x , y ≡ U[0, 1] we have E [min{x , y}] = 1/3
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue in SP Simple auctions with uniform distributions
In a SP auction, the payment is the minimum of the twovalues.
E [revenue] = E [min{x , y}]
Claim: When x , y ≡ U[0, 1] we have E [min{x , y}] = 1/3
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Claim’s proof
Assume that v1 = x .Then, the expected revenue is:
xx
2+ (1− x)x = x − x2
2.
The expectation over all possible x is:
E [min{x , y}] =
∫ 1
0(x − x2
2)dx
=
[x2
2− x3
6
]10
=1
3.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Claim’s proof
Assume that v1 = x .Then, the expected revenue is:
xx
2+ (1− x)x = x − x2
2.
The expectation over all possible x is:
E [min{x , y}] =
∫ 1
0(x − x2
2)dx
=
[x2
2− x3
6
]10
=1
3.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Order statistics
Let v1, . . . , vn be n random variables
The highest realization is called the 1st-order statistic.The second highest is the called 2nd-order statistic.. . .The smallest is the n-th-order statistic.
Example: the uniform distribution, 2 samples.
The expected 1st-order statistic: 2/3Expected efficiency.The expected 2nd-order statistic: 1/3Expected revenue.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Order statistics
Let v1, . . . , vn be n random variables
The highest realization is called the 1st-order statistic.The second highest is the called 2nd-order statistic.. . .The smallest is the n-th-order statistic.
Example: the uniform distribution, 2 samples.
The expected 1st-order statistic: 2/3Expected efficiency.The expected 2nd-order statistic: 1/3Expected revenue.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Order statistics
Let v1, . . . , vn be n random variables
The highest realization is called the 1st-order statistic.The second highest is the called 2nd-order statistic.. . .The smallest is the n-th-order statistic.
Example: the uniform distribution, 2 samples.
The expected 1st-order statistic: 2/3Expected efficiency.The expected 2nd-order statistic: 1/3Expected revenue.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Order statistics
Let v1, . . . , vn be n random variables
The highest realization is called the 1st-order statistic.The second highest is the called 2nd-order statistic.. . .The smallest is the n-th-order statistic.
Example: the uniform distribution, 2 samples.
The expected 1st-order statistic: 2/3Expected efficiency.The expected 2nd-order statistic: 1/3Expected revenue.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Order statistics
Let v1, . . . , vn be n random variables
The highest realization is called the 1st-order statistic.The second highest is the called 2nd-order statistic.. . .The smallest is the n-th-order statistic.
Example: the uniform distribution, 2 samples.
The expected 1st-order statistic: 2/3Expected efficiency.
The expected 2nd-order statistic: 1/3Expected revenue.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Order statistics
Let v1, . . . , vn be n random variables
The highest realization is called the 1st-order statistic.The second highest is the called 2nd-order statistic.. . .The smallest is the n-th-order statistic.
Example: the uniform distribution, 2 samples.
The expected 1st-order statistic: 2/3Expected efficiency.The expected 2nd-order statistic: 1/3Expected revenue.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Order statistics
In general, for the uniform distribution with n samples:
k-th order statistic of n variables is (n + 1− k)/(n + 1)1st-order statistic: n/(n + 1).
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue in FP simple auctions with uniform distributions
In a FP simple auction, vi/2 is a bayesian Nash
Revenue is the highest bid.
Thus, expected revenue is
E [revenue] =E [max{v1/2, v2/2}] =1
2E [max{v1, v2}]
=1
2
2
3=
1
3
Same revenue as in SP simple auctions!
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue in FP simple auctions with uniform distributions
In a FP simple auction, vi/2 is a bayesian Nash
Revenue is the highest bid.
Thus, expected revenue is
E [revenue] =E [max{v1/2, v2/2}] =1
2E [max{v1, v2}]
=1
2
2
3=
1
3
Same revenue as in SP simple auctions!
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue in FP simple auctions with uniform distributions
In a FP simple auction, vi/2 is a bayesian Nash
Revenue is the highest bid.
Thus, expected revenue is
E [revenue] =E [max{v1/2, v2/2}] =1
2E [max{v1, v2}]
=1
2
2
3=
1
3
Same revenue as in SP simple auctions!
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue: FP vs. SP auctions with uniform distributions
Revenue in SP:Bidders bid truthfully.Revenue is 2nd highest bid:
E [revenue] =n − 1
n + 1
Revenue in FP:Bidders bid.Revenue is highest bid:
E [revenue] =E
[max
{n − 1
nv1, . . . ,
n − 1
nvn
}]=n − 1
nE [max{v1, . . . , vn}] =
n − 1
n
n
n + 1=
n − 1
n + 1
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue: FP vs. SP auctions with uniform distributions
Revenue in SP:
Bidders bid truthfully.Revenue is 2nd highest bid:
E [revenue] =n − 1
n + 1
Revenue in FP:Bidders bid.Revenue is highest bid:
E [revenue] =E
[max
{n − 1
nv1, . . . ,
n − 1
nvn
}]=n − 1
nE [max{v1, . . . , vn}] =
n − 1
n
n
n + 1=
n − 1
n + 1
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue: FP vs. SP auctions with uniform distributions
Revenue in SP:Bidders bid truthfully.Revenue is 2nd highest bid:
E [revenue] =n − 1
n + 1
Revenue in FP:Bidders bid.Revenue is highest bid:
E [revenue] =E
[max
{n − 1
nv1, . . . ,
n − 1
nvn
}]=n − 1
nE [max{v1, . . . , vn}] =
n − 1
n
n
n + 1=
n − 1
n + 1
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue: FP vs. SP auctions with uniform distributions
Revenue in SP:Bidders bid truthfully.Revenue is 2nd highest bid:
E [revenue] =n − 1
n + 1
Revenue in FP:
Bidders bid.Revenue is highest bid:
E [revenue] =E
[max
{n − 1
nv1, . . . ,
n − 1
nvn
}]=n − 1
nE [max{v1, . . . , vn}] =
n − 1
n
n
n + 1=
n − 1
n + 1
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue: FP vs. SP auctions with uniform distributions
Revenue in SP:Bidders bid truthfully.Revenue is 2nd highest bid:
E [revenue] =n − 1
n + 1
Revenue in FP:Bidders bid.Revenue is highest bid:
E [revenue] =E
[max
{n − 1
nv1, . . . ,
n − 1
nvn
}]=n − 1
nE [max{v1, . . . , vn}] =
n − 1
n
n
n + 1=
n − 1
n + 1
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue: FP vs. SP auctions with uniform distributions
Revenue in SP:Bidders bid truthfully.Revenue is 2nd highest bid:
E [revenue] =n − 1
n + 1
Revenue in FP:Bidders bid.Revenue is highest bid:
E [revenue] =E
[max
{n − 1
nv1, . . . ,
n − 1
nvn
}]=n − 1
nE [max{v1, . . . , vn}] =
n − 1
n
n
n + 1=
n − 1
n + 1
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue Equivalence Theorem
Assumptions:
vi ‘s are drawn independently from some F on [a, b].F is continuous and strictly increasing.Bidders are risk neutral: utility is a linear function of hiswealth.
Theorem (The Revenue Equivalence Theorem)
Consider two auction such that:
(same allocation) When player i bids v his probability to win isthe same in the two auctions (for all i and v) in equilibrium.
(normalization) If a player bids a (the lowest possible value)he will pay the same amount in both auctions.
Then, in equilibrium, the two auctions earn the same revenue.
Revenue depends most on allocation than on valuations!
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue Equivalence Theorem
Assumptions:vi ‘s are drawn independently from some F on [a, b].F is continuous and strictly increasing.Bidders are risk neutral: utility is a linear function of hiswealth.
Theorem (The Revenue Equivalence Theorem)
Consider two auction such that:
(same allocation) When player i bids v his probability to win isthe same in the two auctions (for all i and v) in equilibrium.
(normalization) If a player bids a (the lowest possible value)he will pay the same amount in both auctions.
Then, in equilibrium, the two auctions earn the same revenue.
Revenue depends most on allocation than on valuations!
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue Equivalence Theorem
Assumptions:vi ‘s are drawn independently from some F on [a, b].F is continuous and strictly increasing.Bidders are risk neutral: utility is a linear function of hiswealth.
Theorem (The Revenue Equivalence Theorem)
Consider two auction such that:
(same allocation) When player i bids v his probability to win isthe same in the two auctions (for all i and v) in equilibrium.
(normalization) If a player bids a (the lowest possible value)he will pay the same amount in both auctions.
Then, in equilibrium, the two auctions earn the same revenue.
Revenue depends most on allocation than on valuations!
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue Equivalence Theorem
Assumptions:vi ‘s are drawn independently from some F on [a, b].F is continuous and strictly increasing.Bidders are risk neutral: utility is a linear function of hiswealth.
Theorem (The Revenue Equivalence Theorem)
Consider two auction such that:
(same allocation) When player i bids v his probability to win isthe same in the two auctions (for all i and v) in equilibrium.
(normalization) If a player bids a (the lowest possible value)he will pay the same amount in both auctions.
Then, in equilibrium, the two auctions earn the same revenue.
Revenue depends most on allocation than on valuations!AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue in All-pay auction
Rules
Sealed bidHighest bid winsEveryone pay their bid
Equilibrium with the uniform distribution is
b(v) =n − 1
nvn
Revenue?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue in All-pay auction
Rules
Sealed bidHighest bid winsEveryone pay their bid
Equilibrium with the uniform distribution is
b(v) =n − 1
nvn
Revenue?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue in All-pay auction
Rules
Sealed bidHighest bid winsEveryone pay their bid
Equilibrium with the uniform distribution is
b(v) =n − 1
nvn
Revenue?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue in All-pay auction
Rules
Sealed bidHighest bid winsEveryone pay their bid
Equilibrium with the uniform distribution is
b(v) =n − 1
nvn
Revenue?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue in All-pay auction
Rules
Sealed bidHighest bid winsEveryone pay their bid
Equilibrium with the uniform distribution is
b(v) =n − 1
nvn
Revenue?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue in All-pay auction
Expected payment per each player: her bid
Each bidder bids b(v) = n−1n vn.
Expected payment for each bidder:∫ 1
0
n − 1
nvndv =
n − 1
n
[vn+1
n + 1
]10
=1
n
n − 1
n + 1
Revenue for n bidders
E [revenue] =n − 1
n + 1.
Again revenue equivalence!
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue in All-pay auction
Expected payment per each player: her bid
Each bidder bids b(v) = n−1n vn.
Expected payment for each bidder:∫ 1
0
n − 1
nvndv =
n − 1
n
[vn+1
n + 1
]10
=1
n
n − 1
n + 1
Revenue for n bidders
E [revenue] =n − 1
n + 1.
Again revenue equivalence!
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue in All-pay auction
Expected payment per each player: her bid
Each bidder bids b(v) = n−1n vn.
Expected payment for each bidder:∫ 1
0
n − 1
nvndv =
n − 1
n
[vn+1
n + 1
]10
=1
n
n − 1
n + 1
Revenue for n bidders
E [revenue] =n − 1
n + 1.
Again revenue equivalence!
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue in All-pay auction
Expected payment per each player: her bid
Each bidder bids b(v) = n−1n vn.
Expected payment for each bidder:∫ 1
0
n − 1
nvndv =
n − 1
n
[vn+1
n + 1
]10
=1
n
n − 1
n + 1
Revenue for n bidders
E [revenue] =n − 1
n + 1.
Again revenue equivalence!
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue in All-pay auction
Expected payment per each player: her bid
Each bidder bids b(v) = n−1n vn.
Expected payment for each bidder:∫ 1
0
n − 1
nvndv =
n − 1
n
[vn+1
n + 1
]10
=1
n
n − 1
n + 1
Revenue for n bidders
E [revenue] =n − 1
n + 1.
Again revenue equivalence!
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue in All-pay auction
Expected payment per each player: her bid
Each bidder bids b(v) = n−1n vn.
Expected payment for each bidder:∫ 1
0
n − 1
nvndv =
n − 1
n
[vn+1
n + 1
]10
=1
n
n − 1
n + 1
Revenue for n bidders
E [revenue] =n − 1
n + 1.
Again revenue equivalence!
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
All-pay auctions: examples
crowdsourcing over the internet:
First person to complete a task for me gets a reward.A group of people invest time in the task. (=payment)Only the winner gets the reward.
Advertising auction:
Collect suggestion for campaigns, choose a winner.All advertiser incur cost of preparing the campaign.Only one wins.
War of attrition
Animals invest (b1,b2) in fighting.Maynard Smith, J. (1974) Theory of games and the evolutionof animal conflicts.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
All-pay auctions: examples
crowdsourcing over the internet:
First person to complete a task for me gets a reward.A group of people invest time in the task. (=payment)Only the winner gets the reward.
Advertising auction:
Collect suggestion for campaigns, choose a winner.All advertiser incur cost of preparing the campaign.Only one wins.
War of attrition
Animals invest (b1,b2) in fighting.Maynard Smith, J. (1974) Theory of games and the evolutionof animal conflicts.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
All-pay auctions: examples
crowdsourcing over the internet:
First person to complete a task for me gets a reward.A group of people invest time in the task. (=payment)Only the winner gets the reward.
Advertising auction:
Collect suggestion for campaigns, choose a winner.All advertiser incur cost of preparing the campaign.Only one wins.
War of attrition
Animals invest (b1,b2) in fighting.Maynard Smith, J. (1974) Theory of games and the evolutionof animal conflicts.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
All-pay auctions: examples
crowdsourcing over the internet:
First person to complete a task for me gets a reward.A group of people invest time in the task. (=payment)Only the winner gets the reward.
Advertising auction:
Collect suggestion for campaigns, choose a winner.All advertiser incur cost of preparing the campaign.Only one wins.
War of attrition
Animals invest (b1,b2) in fighting.Maynard Smith, J. (1974) Theory of games and the evolutionof animal conflicts.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
All-pay auctions: examples
crowdsourcing over the internet:
First person to complete a task for me gets a reward.A group of people invest time in the task. (=payment)Only the winner gets the reward.
Advertising auction:
Collect suggestion for campaigns, choose a winner.All advertiser incur cost of preparing the campaign.Only one wins.
War of attrition
Animals invest (b1,b2) in fighting.Maynard Smith, J. (1974) Theory of games and the evolutionof animal conflicts.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
All-pay auctions: examples
crowdsourcing over the internet:
First person to complete a task for me gets a reward.A group of people invest time in the task. (=payment)Only the winner gets the reward.
Advertising auction:
Collect suggestion for campaigns, choose a winner.All advertiser incur cost of preparing the campaign.Only one wins.
War of attrition
Animals invest (b1,b2) in fighting.Maynard Smith, J. (1974) Theory of games and the evolutionof animal conflicts.
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue
At equilibrium neither SP nor FP lead the maximum possiblebenefit to the seller.
Can we get a better understanding of revenue?
Can we have a truthful auction giving maximum revenue?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue
At equilibrium neither SP nor FP lead the maximum possiblebenefit to the seller.
Can we get a better understanding of revenue?
Can we have a truthful auction giving maximum revenue?
AGT-MIRI Single item auctions
Mechanism designAuctions:Context and Definitions
Single item auctionsAnalyzing auctions
Revenue in auctions
Maximal revenueSP auctionsFP auctionsRevenue equivalenceAll-pay auctions
Revenue
At equilibrium neither SP nor FP lead the maximum possiblebenefit to the seller.
Can we get a better understanding of revenue?
Can we have a truthful auction giving maximum revenue?
AGT-MIRI Single item auctions