Unknotting operations for bered knots and pseudo- ber surfaces€¦ · Yukari Funakoshi Unknotting...

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. . . . . . Introduction and Preliminaries Pre-fiber surface pseudo-fiber surface of level n . . Unknotting operations for fibered knots and pseudo-fiber surfaces Yukari Funakoshi Nara Women’s University December 21, 2013 Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfac

Transcript of Unknotting operations for bered knots and pseudo- ber surfaces€¦ · Yukari Funakoshi Unknotting...

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .

    ......

    Unknotting operations for fibered knots andpseudo-fiber surfaces

    Yukari Funakoshi

    Nara Women’s University

    December 21, 2013

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .Definition..

    ......

    n-component link : S11 ∪ S12 ∪ · · · ∪ S1n ↪→ S3mutually disjoint oriented 1-spheres embedded in S3

    knot: one component link

    .Example..

    ......

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .Definition (unknotting operation)..

    ......

    .Definition..

    ......

    K :knot,u(K ):=min{ the number of unknotting operations

    required to obtain a trivial knot from K }: unknotting number of K

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .. Sharlemann-Thompson’s work on unknotting number

    L: link.Definition (Seifert surface)..

    ......

    A Seifert surface S for L isa compact oriented surface w/o closed comp. (⊂ S3) s.t. ∂S = L

    Fact. There exists Seifert surface, for ∀L..Definition (minimal genus Seifert surface, genus of a knot)..

    ......

    The genus of a knot K isg(K ) := min{genus(F )|F : Seifert surface for K}A Seifert surface S for K isminimal genus if genus(S) = g(K ).

    Note. K : trivial knot ⇔ g(K ) = 0

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .Theorem (Scharlemann-Thompson)..

    ......

    L, L′: knotL → L′: unknotting operationg(L′) < g(L)∃S : minimal genus Seifert surface of L

    s.t. S is a plumbing of a surface and Hopf band,

    and

    M. Sharlemann, A. Thomnpson, Link genus and Conway moves,

    Comment. Math. Helv. 64(1989), no.4, 527-53Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .Definition (sutured manifold)..

    ......

    (M, γ)is a sutured manifold.

    ⇐⇒defM: an oriented 3−manifold

    γ : union of annuli (⊂ ∂M)

    with s(γ) : oriented core curves of γ ,where each component of R(γ) := ∂M \ Intγ is orientedso that the orientation meets s(γ).

    (Each component of s(γ) is called a suture.)

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    Fix an orientation of M. Then:

    R+(γ)(R−(γ) resp.)

    :=the union of the component of R(γ)whose normal vector points out (into resp.) M.

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .Example (product sutured manifold)..

    ......

    S : compactorientable surface

    M = S × [0, 1]γ = ∂S × [0, 1]

    Then (M, γ) is a sutured manifolds.t. R+(γ) = S × {1}

    R−(γ) = S × {0}

    Such (M, γ) is called a product sutured manifold.

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    L : linkS : Seifert surface for LE (L)(:= S3 \ IntN(L))

    : exterior of L(For simplicitywe denote S ∩ E (L) by S .)N = N(S ;E (L))δ = N ∩ ∂E (L)

    The product sutured manifold (N, δ) is calledthe sutured manifold obtained from S .

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .Definition (complementary sutured manifold)..

    ......

    Nc = cl(E (L) \ N)δc = cl(∂E (L) \ δ)R±(δ

    c) = R∓(δ)

    (Nc , δc) is called the complementary sutured manifold for S.

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    L : link, S : Seifert surface for L.Definition (fiber surface)..

    ......

    S is a fiber surface , if :the complementary sutured manifold

    is a product sutured manifold.

    .Definition (fibered link)..

    ......

    L is a fibered link if∃S : Seifert surface for L s.t. S is a fiber surface.

    .Example..

    ......

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    T. Kobayashi, Fiberd links and unknotting operations,Osaka J. Math. 26(1989), 699-742

    L: linkS : Seifert surface for L(Nc , δc):

    complementary sutured manifold for S.Definition (pre-fiber surface)..

    ......

    S is a pre-fiber surface, if:∃D±(⊂ Nc): mutually disjoint disks

    s.t. R±(δc)∩D± = ∂D±: essential in R±(δc)

    (such disk is called a compressing disk for R±(δc)),

    and (Nc ′, δc) is a product sutured manifold,

    where Nc ′ is a 3-manifold obtained from Nc

    by cutting along D+ ∪ D−.

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .. Examples of pre-fiber surfaces

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .Theorem (Kobayashi)..

    ......

    Suppose L: fibered knot s.t.u(L) = 1.

    L: fibered L′: trivial

    S : fiber surface

    Then S ′ is a pre-fiber surface.

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .Theorem..

    ......

    S :pre-fiber surfacewith canonical compressing disks D̄+,D̄−.

    Let α be an arc properly embedded in S .s.t. α ∩ D̄+: 1-point,

    α ∩ D̄−: 1-point.

    The surface obtained from Sby applying a twist along α is a fiber surface.

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .. Motivation:

    Generalize the above results

    for fibered knots with unknotting numbers > 1.

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .. A generalization of pre-fiber surface.

    Let L: linkS : Seifert surface

    (Nc , δc): complementary sutured manifold for S

    .Definition (pseudo-fiber surface of level n)..

    ......

    ・・・

    ・・・

    For n ≥ 0, S is a pseudo-fiber surface of level n, if:

    ∃D±1 , . . . ,D±n:mutually disjoint compressing disks of R±(δ

    c)

    s.t. (Nc ′, δc)is a product sutured manifold,where Nc ′ is a 3-manifold obtained from Nc

    by cutting alongD+1 ∪ · · · ∪ D+n ∪ D

    −1 ∪ · · · ∪ D−n

    S is a pseudo-fiber surface of level 0 ⇔ S is a fiber surfaceS is a pseudo-fiber surface of level 1 ⇔ S is a pre-fiber surface

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .. A generalization of Theorem (Kobayashi)

    .Theorem (Kobayashi)..

    ......

    S :pre-fiber surface with canonical compressing disks D̄+,D̄−.Let α be an arc properly embedded in S s.t. α ∩ D̄+: 1-point,

    α ∩ D̄−: 1-point.The surface obtained from S by applying a twist along α is a fiber surface.

    .Theorem..

    ......

    Let S : a pseudo-fiber surface of level nα1, . . . , αp: mutually disjoint arcs properly embedded in S

    (p ≤ n)Suppose that ∃D̄+1 , . . . , D̄+n , D̄−1 , . . . , D̄

    −n

    : a system of canonical compressing diskss.t. αi ∩ D̄±j = ∅ for ∀i , j (i ̸= j),

    αi ∩ ∂D̄+i (∂D̄−i resp.): 1-point. (i = 1, . . . , p)

    Thenthe surface obtained from S by twisting along α1 ∪ · · · ∪ αpis a pseudo-fiber surface of level n − p.

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .Theorem (Kobayashi)..

    ......

    Suppose L: fibered knot s.t.u(L) = 1.

    S : fiber surface S ′: pre-fiber surface

    .Definition (Ascending sequence of pseudo-fiber surfaces)..

    ......

    A sequence of pseudo-fiber surfaces Si of level piS0 → S1 → · · · → Si → Si+1 → · · · → Sn

    where pi ≤ pi+1 (i = 0, 1, . . . , n − 1)p0 = 0

    is an ascending sequence of pseudo-fiber surface if:

    ∃α(i)1 , . . . , α(i)qi : mutually disjoint arcs properly embedded in Si

    s.t. Si+1 is obtained from Si by twisting along α(i)1 ∪ · · · ∪α

    (i)qi .

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .Question..

    ......

    For each fibered knot K ,

    does there exist an ascending sequence of pseudo-fiber surfacesrealizing the unknotting number u(K )?

    More precisely,does there exist an ascending sequence of pseudo-fiber surfaces

    S0 → S1 → · · · → Sn

    (with levels pi , arcs α(i)1 , . . . , α

    (i)qi as above)

    such that ∂S0 = K , ∂Sn = trivial knot, andu(K ) = q0 + q1 + · · ·+ qn−1?

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .. Torus knot

    Notation:T : unknotted torus(⊂ S3)

    Fix an oriented meridian curve, andan oriented longitude curve on T .

    Let p, q: relatively prime integers,p, q ̸= 0

    .Definition (Torus knot of type (p, q))..

    ......

    T (p, q) is a knot embedded in T which wrapsp times along the meridian andq times along the longitude.Such T (p, q) is called a torus knot of type (p, q).

    It is known that each torus knot is a fibered knot.

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .Theorem 2.1..

    ......

    ...1 A torus knot T (p, q) is trivial if and only ifeither p = ±1 or q = ±1.

    ...2 Two non-trivial torus knotsT (p, q) and T (p′, q′) are equivalent if and only if(p′, q′) is equal to one of the following,

    (±p,±q), (±q,±p), (±p,∓q), (±q,∓p).

    T (p, q): torus knot of type (p, q), where 0 < p < q.Theorem (Kronheimer-Mrowka)..

    ......u(T (p, q)) =

    (p − 1)(q − 1)2

    Kronheimer, P. B.; Mrowka, T. S. , Gauge theory for embedded

    surfaces, I, Topology 32 (1993), no.4, 773―826Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .. Consider the fractional expansion (0 < p < q)

    q

    p= a0 +

    1

    a1 +1

    . . .1

    am−1 +1

    pm−1

    , (ai > 0, pm−1 > 1)

    Euclidian algorithmpi−1 = piai+1 + pi+1(0 ≤ i ≤ m − 2, p−1 = q, p0 = p, 0 < pi+1 < pi )

    7

    5= 1 +

    2

    5= 1 +

    1

    5

    2

    = 1 +1

    2 +1

    2

    (7 = 5× 1 + 2) (5 = 2× 2 + 1)Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .Theorem 5.1..

    ......

    T (p, q): torus knot of type (p, q)∃ S0 → S1 → S2 → · · · → Sm

    : an ascending sequence of pseudo-fiber surfaces for T (p, q)realizing the unknotting number of T (p, q) with length m,

    s.t. the level of Si is∑i

    k=0(pk−1 − 1)ak−1.

    .Example 5.2..

    ......

    Note that u(T (5, 7)) = 12, Note7

    5= 1 +

    1

    2 +1

    2∃ S0 → S1 → S2 : ascending sequence

    realizing the unknotting number of T (5, 7),where the level of S1 is 4,

    the level of S2 is 6.

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    Notation.

    Bn: n-braid groupσ1, . . . , σn−1: standard generaters of Bnβ ∈ Bn ⇒ β̂: closure of β

    Fact.

    T (p, q) = ̂(σ1 · · ·σq−1)p

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    Recall:q

    p= a0 +

    p1

    p(a0 > 0, 0 < p1 < p, 0 < p < q)

    .Key Fact 1..

    ......

    a0 ×p(p − 1)

    2simultaneous unknotting operations

    T (p, q) −→−→−→−→−→−→−→−→−→−→−→ T (p1, p)

    This Fact is proved later.

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    Recall:q

    p= a0 +

    p1

    p(a0 > 0, 0 < p1 < p, 0 < p < q)

    .Key Fact 1..

    ......

    a0 ×p(p − 1)

    2simultaneous unknotting operations

    T (p, q) −→−→−→−→−→−→−→−→−→−→−→ T (p1, p)

    This Fact is proved later.

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    Note that: by Kronheimer-Mrowka,u(T (p, q))− u(T (p1, p))

    =(p − 1)(q − 1)

    2− (p1 − 1)(p − 1)

    2= a0 ×

    p(p − 1)2

    By this observation together with Fact, we seeu(T (p, q)) is realized byT (p, q) → T (p, p1) = T (p1, p) → T (p1, p2) = T (p2, p1) → · · ·

    a0p(p − 1)

    2a1

    p1(p1 − 1)2

    · · · → T (pm−1, 1): trivial knotWe will see this sequence gives the ascending sequence ofpseudo-fiber surface in Theorem 5.1.

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    Note that: by Kronheimer-Mrowka,u(T (p, q))− u(T (p1, p))

    =(p − 1)(q − 1)

    2− (p1 − 1)(p − 1)

    2= a0 ×

    p(p − 1)2

    By this observation together with Fact, we seeu(T (p, q)) is realized byT (p, q) → T (p, p1) = T (p1, p) → T (p1, p2) = T (p2, p1) → · · ·

    a0p(p − 1)

    2a1

    p1(p1 − 1)2

    · · · → T (pm−1, 1): trivial knot

    .Key Fact 2........The twists in Key Fact 1 produces a pseudo-fiber surface.

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    Let β = σϵ1i1 σϵ2i2· · ·σϵmim (∈ Bn), ϵi = ±1

    Sβ :=Seifert surface obtained from β̂by applying Seifert algorithm.

    ⇔ Sβ is obtained from n horizontal disks by attaching m half twistbands according to the representative σϵ1i1 σ

    ϵ2i2· · ·σϵmim .

    Notation.

    τ ϵ1i1 τϵ2i2· · · τ ϵmim denotes Sβ,

    where τϵjij

    denotes the half twist band corresponding to σϵjij

    Let γ = σν1j1 σν2j2· · ·σνℓjℓ ∈ Bq be another braid such that γ̄ = β̄. We

    say: Sβ = τϵ1i1τ ϵ2i2 · · · τ

    ϵmim

    and Sγ = τν1j1τν2j2 · · · τ

    νℓjℓ

    are equivalent

    (denoted by τ ϵ1i1 τϵ2i2· · · τ ϵmim = τ

    ν1j1τν2j2 · · · τ

    νℓjℓ).

    if there is an ambient isotopy of S3 transforming Sβ to Sγ .

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .. 関係式の例

    A,B: words in τ ’s.lemma4.1..

    ......

    Sβ = A · τ ϵii τϵjj · B: be the Seifert surface for β̄.

    Suppose |i − j | > 1.Then A · τ ϵii τ

    ϵjj · B = A · τ

    ϵjj τ

    ϵii · B.

    .Lemma..

    ......

    Sβ = A · τ±1i τi+1τi · B: be the Seifert surface for β̄.Then we have A · τ±1i τi+1τi · B = A · τi+1τiτ

    ±1i+1 · B

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .. Extended Notation.

    τ−1i τi in A · τ−1i τi · B

    does not give a “trivial part”,but a tube attached to A · B.

    We shall denote the subsurface as in Figure by

    (i + 1i

    ),

    and the Seifert surface in the right side of Figure by A

    (i + 1i

    )B.

    A · τ−1i+1τ−1i τiτi+1 · B A

    (i + 1 i + 2i i + 1

    )B

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .. 関係式の例

    .lemma4.3..

    ......

    For each j ∈ {1, . . . , n − 1} \ {k, k + 1}, we have

    A ·(

    i + 1 · · · k + 1i · · · k

    )τ±1j ·B=A ·τ

    ±1j

    (i + 1 · · · k + 1i · · · k

    )·B

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .. 関係式の例.lemma4.4..

    ......

    For each pair r , k (2 ≤ r ≤ k ≤ p − 1), we have

    Aτr−1 · · · τk(

    r · · · kr − 1 · · · k − 1

    )B

    = A

    (r + 1 · · · k + 1r · · · k

    )τr−1 · · · τkB.

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .. 関係式の例.lemma4.5..

    ......

    For any pairs of pair of integer(r , s) with (2 ≤ r ≤ s ≤ p) and (t, u) with (2 ≤ t ≤ u ≤ p),

    we have A

    (t · · · u

    t − 1 · · · u − 1

    )(r · · · s

    r − 1 · · · s − 1

    )B

    = A

    (r · · · s

    r − 1 · · · s − 1

    )(t · · · u

    t − 1 · · · u − 1

    )B

    < s ̸= u>

    ...

    ...Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    .. 関係式の例.lemma4.5..

    ......

    For any pairs of pair of integer(r , s) with (2 ≤ r ≤ s ≤ p) and (t, u) with (2 ≤ t ≤ u ≤ p),

    we have A

    (t · · · u

    t − 1 · · · u − 1

    )(r · · · s

    r − 1 · · · s − 1

    )B

    = A

    (r · · · s

    r − 1 · · · s − 1

    )(t · · · u

    t − 1 · · · u − 1

    )B

    < s = u>

    ...

    ......

    ...

    ...

    ...

    ...

    ...

    ...

    ...

    ...

    ...

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (σ1σ2σ3σ4)7

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ1τ2τ3τ4)7

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ1τ2τ3τ4)7

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ1τ2τ3τ4)7

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)(τ1τ2τ3τ4)(τ1τ2τ3τ4)(τ1τ2τ3τ4)3

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

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    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ−11 τ−12 τ

    −13 τ

    −14 )(τ

    −11 τ

    −12 τ

    −13 τ4)(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ−11 )(τ−12 τ

    −13 τ

    −14 )(τ

    −11 τ

    −12 τ

    −13 τ4 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ−11 τ1 )(τ−12 τ

    −13 τ

    −14 )(τ

    −11 τ

    −12 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ−11 τ−12 τ

    −13 τ

    −14 )(τ

    −11 τ

    −12

    ::::::τ−13 τ4)(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −13 )(τ

    −11 τ

    −12

    ::::::)(τ−14 τ

    −13 τ4 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −13 )(τ

    −11 τ

    −12 )( τ3 τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −11 )(τ

    −13 τ

    −12 τ3 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −11 )( τ2 τ

    −13 τ

    −12 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 )(τ

    −12 τ

    −11 τ2 )(τ

    −13 τ

    −12 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 )( τ1 τ

    −12 τ

    −11 )(τ

    −13 τ

    −12 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ−11 τ−12 τ

    −13 τ

    −14 )(τ

    −11 τ

    −12

    ::::::τ−13 τ4)(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −13 )(τ

    −11 τ

    −12

    ::::::)(τ−14 τ

    −13 τ4 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −13 )(τ

    −11 τ

    −12 )( τ3 τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −11 )(τ

    −13 τ

    −12 τ3 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −11 )( τ2 τ

    −13 τ

    −12 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 )(τ

    −12 τ

    −11 τ2 )(τ

    −13 τ

    −12 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 )( τ1 τ

    −12 τ

    −11 )(τ

    −13 τ

    −12 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ−11 τ−12 τ

    −13 τ

    −14 )(τ

    −11 τ

    −12

    ::::::τ−13 τ4)(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −13 )(τ

    −11 τ

    −12

    ::::::)(τ−14 τ

    −13 τ4 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −13 )(τ

    −11 τ

    −12 )( τ3 τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −11 )(τ

    −13 τ

    −12 τ3 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −11 )( τ2 τ

    −13 τ

    −12 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 )(τ

    −12 τ

    −11 τ2 )(τ

    −13 τ

    −12 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 )( τ1 τ

    −12 τ

    −11 )(τ

    −13 τ

    −12 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ−11 τ−12 τ

    −13 τ

    −14 )(τ

    −11 τ

    −12

    ::::::τ−13 τ4)(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −13 )(τ

    −11 τ

    −12

    ::::::)(τ−14 τ

    −13 τ4 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −13 )(τ

    −11 τ

    −12 )( τ3 τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −11 )(τ

    −13 τ

    −12 τ3 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −11 )( τ2 τ

    −13 τ

    −12 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 )(τ

    −12 τ

    −11 τ2 )(τ

    −13 τ

    −12 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 )( τ1 τ

    −12 τ

    −11 )(τ

    −13 τ

    −12 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ−11 τ−12 τ

    −13 τ

    −14 )(τ

    −11 τ

    −12

    ::::::τ−13 τ4)(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −13 )(τ

    −11 τ

    −12

    ::::::)(τ−14 τ

    −13 τ4 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −13 )(τ

    −11 τ

    −12 )( τ3 τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −11 )(τ

    −13 τ

    −12 τ3 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −11 )( τ2 τ

    −13 τ

    −12 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 )(τ

    −12 τ

    −11 τ2 )(τ

    −13 τ

    −12 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 )( τ1 τ

    −12 τ

    −11 )(τ

    −13 τ

    −12 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ−11 τ−12 τ

    −13 τ

    −14 )(τ

    −11 τ

    −12

    ::::::τ−13 τ4)(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −13 )(τ

    −11 τ

    −12

    ::::::)(τ−14 τ

    −13 τ4 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −13 )(τ

    −11 τ

    −12 )( τ3 τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −11 )(τ

    −13 τ

    −12 τ3 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −11 )( τ2 τ

    −13 τ

    −12 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 )(τ

    −12 τ

    −11 τ2 )(τ

    −13 τ

    −12 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 )( τ1 τ

    −12 τ

    −11 )(τ

    −13 τ

    −12 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ−11 τ−12 τ

    −13 τ

    −14 )(τ

    −11 τ

    −12

    ::::::τ−13 τ4)(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −13 )(τ

    −11 τ

    −12

    ::::::)(τ−14 τ

    −13 τ4 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −13 )(τ

    −11 τ

    −12 )( τ3 τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −11 )(τ

    −13 τ

    −12 τ3 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 τ

    −12 τ

    −11 )( τ2 τ

    −13 τ

    −12 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 )(τ

    −12 τ

    −11 τ2 )(τ

    −13 τ

    −12 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    ↓(τ−11 )( τ1 τ

    −12 τ

    −11 )(τ

    −13 τ

    −12 )(τ

    −14 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ−11 )(τ−12 τ

    −13 τ

    −14 )(τ

    −11 τ

    −12 τ

    −13 τ4 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ−11 τ1 )(τ−12 τ

    −13 τ

    −14 )(τ

    −11 τ

    −12 τ

    −13 )(τ

    −11 τ

    −12 τ3τ4)(τ

    −11 τ2τ3τ4)(τ1τ2τ3τ4)

    3

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ−11 τ1 )(τ−12 τ

    −13 τ

    −14 )(τ

    −11 )(τ

    −12 τ

    −13 )(τ

    −11 τ

    −12 τ3 τ4)(τ

    −11 τ2τ3τ4)

    (τ1τ2τ3τ4)3

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ−11 τ1 )(τ−12 τ

    −13 τ

    −14 )(τ

    −11 τ1 )(τ

    −12 τ

    −13 )(τ

    −11 τ

    −12 τ4)(τ

    −11 τ2τ3τ4)

    (τ1τ2τ3τ4)3

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ−11 τ1 )(τ−12 τ

    −13 τ

    −14 )(τ

    −11 τ1 )(τ

    −12 τ

    −13 )(τ

    −11 )(τ

    −12 τ4)(τ

    −11 τ2 τ3τ4)

    (τ1τ2τ3τ4)3

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ−11 τ1 )(τ−12 τ

    −13 τ

    −14 )(τ

    −11 τ1 )(τ

    −12 τ

    −13 )(τ

    −11 τ1 )(τ

    −12 τ4)(τ

    −11 τ3τ4)

    (τ1τ2τ3τ4)3

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ−11 τ1 )(τ−12 τ

    −13 τ

    −14 )(τ

    −11 τ1 )(τ

    −12 τ

    −13 )(τ

    −11 τ1 )(τ

    −12 τ4)

    (τ−11 τ3τ4)(τ1τ2τ3τ4)(τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ−11 τ1 )(τ−12 τ

    −13 τ

    −14 )(τ

    −11 τ1 )(τ

    −12 τ

    −13 )(τ

    −11 τ1 )(τ

    −12 τ4)

    (τ−11 )(τ3τ4)( τ1 τ2τ3τ4)(τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ−11 τ1 )(τ−12 τ

    −13 τ

    −14 )(τ

    −11 τ1 )(τ

    −12 τ

    −13 )(τ

    −11 τ1 )(τ

    −12 τ4)

    (τ−11 τ1 )(τ3τ4)(τ2τ3τ4)(τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )(τ−12 τ

    −13 τ

    −14 )

    (21

    )(τ−12 τ

    −13 )

    (21

    )(τ−12 τ4)(

    21

    )(τ3τ4)(τ2τ3τ4)(τ1τ2τ3τ4)

    2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )(τ−12 τ

    −13 τ

    −14 )

    (21

    )::::

    (τ−12 τ−13 )

    (21

    )(τ−12 τ4 )(

    21

    )(τ3τ4)(τ2τ3τ4)(τ1τ2τ3τ4)

    2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )(τ−12 τ

    −13 τ

    −14 )

    (21

    )::::

    (τ−12 τ−13 τ4 )

    (21

    )(τ−12 )(

    21

    )(τ3τ4)(τ2τ3τ4)(τ1τ2τ3τ4)

    2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )(τ−12

    (21

    )::::

    )(τ−13 τ−14 )(τ

    −12 τ

    −13 τ4 )

    (21

    )(τ−12 )(

    21

    )(τ3τ4)(τ2τ3τ4)(τ1τ2τ3τ4)

    2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )(τ−12

    (21

    )::::

    τ2 )(τ−13 τ

    −14 )(τ

    −12 τ

    −13 )

    (21

    )(τ−12 )(

    21

    )(τ3τ4)(τ2τ3τ4)(τ1τ2τ3τ4)

    2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )(τ−13 τ

    −14 )(τ

    −12 τ

    −13 )

    (21

    )(τ−12 )(

    21

    )(τ3τ4)(τ2τ3τ4)(τ1τ2τ3τ4)

    2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )(τ−13 τ

    −14 )(τ

    −12 τ

    −13 )

    (21

    )(τ−12 )

    (21

    )( τ3 τ4)(τ2τ3τ4)

    (τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )(τ−13 τ

    −14 )(τ

    −12 τ

    −13 )

    (21

    )::::

    (τ−12 )

    (21

    )( τ3 τ4)(τ2τ3τ4)

    (τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )(τ−13 τ

    −14 )(τ

    −12

    (21

    )::::

    )(τ−13 )(τ−12 )

    (21

    )( τ3 τ4)(τ2τ3τ4)

    (τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )(τ−13 τ

    −14 )(τ

    −12

    (21

    )::::

    τ2 )(τ−13 )(τ

    −12 )

    (21

    )(τ4)(τ2τ3τ4)

    (τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )(τ−13 τ

    −14 )(τ

    −12

    (21

    )::::

    τ2 )(τ−13 )(τ

    −12 )

    (21

    )::::

    (τ4)( τ2 τ3τ4)

    (τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )(τ−13 τ

    −14 )(τ

    −12

    (21

    )::::

    τ2 )(τ−13 )(τ

    −12

    (21

    )::::

    )(τ4)( τ2 τ3τ4)

    (τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )(τ−13 τ

    −14 )(τ

    −12

    (21

    )::::

    τ2 )(τ−13 )(τ

    −12

    (21

    )::::

    τ2 )(τ4)(τ3τ4)

    (τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )(τ−13 τ

    −14 )

    (2 31 2

    )(τ−13 )

    (2 31 2

    )(τ4)(τ3τ4)

    (τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )(τ−13 τ

    −14 )

    (2 31 2

    ):::::::

    (τ−13 )

    (2 31 2

    )( τ4 )(τ3τ4)

    (τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )(τ−13

    (2 31 2

    ):::::::

    )(τ−14 )(τ−13 )( τ4 )

    (2 31 2

    )(τ3τ4)

    (τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )(τ−13

    (2 31 2

    ):::::::

    τ3 )(τ−14 )(τ

    −13 )

    (2 31 2

    )(τ3τ4)

    (τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ−14 )(τ

    −13 )

    (2 31 2

    )(τ3τ4)

    (τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ−14 )(τ

    −13

    (2 31 2

    )τ3)(τ4)

    (τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ−14 )

    (2 3 41 2 3

    )(τ4)

    (τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ−14

    (2 3 41 2 3

    )τ4)(τ1τ2τ3τ4)

    2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )·(2 3 4 51 2 3 4

    ):::::::::::::

    · (τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )·(2 3 4 51 2 3 4

    ):::::::::::::

    · (τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )·(2 3 4 51 2 3 4

    ):::::::::::::

    · (τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )·(2 3 4 51 2 3 4

    ):::::::::::::

    · (τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )·(2 3 4 51 2 3 4

    ):::::::::::::

    · (τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )·(2 3 4 51 2 3 4

    ):::::::::::::

    · (τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )·(2 3 4 51 2 3 4

    ):::::::::::::

    · (τ1τ2τ3τ4)2

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)

    2(2 3 4 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)

    2(2 3 4 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)

    2(2 3 4 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)

    2(2 3 4 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)

    2(2 3 4 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)

    2(2 3 4 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)

    2 (2 3 4 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)

    2

    (2 3 4 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)

    2

    (2 3 4 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (2 3 4 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (2 3 4 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (3 4 5 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (3 4 5 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (3 4 5 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (4 5 5 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (4 5 5 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (5 5 5 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (5 5 5 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (5 5 5 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (5 5 5 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (5 5 5 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (5 5 5 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (5 5 5 51 2 3 4

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (5 5 5 52 3 4 5

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (5 5 5 52 3 4 5

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (5 5 5 53 4 5 5

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (5 5 5 53 4 5 5

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (5 5 5 54 5 5 5

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (5 5 5 54 5 5 5

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (5 5 5 55 5 5 5

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (5 5 5 55 5 5 5

    ):::::::::::::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)Σ

    14

    ::

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )::::::::::

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )::::::::::

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )::::::::::

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )::::::::::

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )::::::::::

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )::::::::::

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )::::::::::

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )::::::::::

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )::::::::::

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )::::::::::

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )::::::::::

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )::::::::::

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )::::::::::

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )::::::::::

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )::::::::::

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )·(2 3 41 2 3

    )::::::::::

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (2 3 41 2 3

    )::::::::::

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (2 3 41 2 3

    )::::::::::

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )· (τ1τ2τ3τ4)

    (3 4 52 3 4

    )::::::::::

    (τ1τ2τ3τ4)

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )· (τ1τ2τ3τ4)

    (3 4 52 3 4

    )::::::::::

    (τ1τ2τ3τ4)

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )· (τ1τ2τ3τ4)

    (3 4 52 3 4

    )::::::::::

    (τ1τ2τ3τ4)

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )· (τ1τ2τ3τ4)

    (3 4 53 4 5

    )::::::::::

    (τ1τ2τ3τ4)

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (3 4 53 4 5

    )::::::::::

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (3 4 53 4 5

    )::::::::::

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (3 4 54 5 5

    )::::::::::

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (3 4 54 5 5

    )::::::::::

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (3 4 55 5 5

    )::::::::::

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (3 4 55 5 5

    )::::::::::

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (3 4 55 5 5

    )::::::::::

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (3 4 55 5 5

    )::::::::::

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (4 5 55 5 5

    )::::::::::

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (4 5 55 5 5

    )::::::::::

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (5 5 55 5 5

    )::::::::::

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (5 5 55 5 5

    )::::::::::

    Σ14Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)Σ13

    ::

    Σ14

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14, Σ13

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(2 31 2

    ):::::::

    · (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14, Σ13

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (2 31 2

    ):::::::

    Σ14, Σ13

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )· (τ1τ2τ3τ4)

    (3 42 3

    ):::::::

    (τ1τ2τ3τ4)

    Σ14, Σ13

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )· (τ1τ2τ3τ4)

    (3 42 3

    ):::::::

    (τ1τ2τ3τ4)

    Σ14, Σ13

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )·(4 53 4

    ):::::::

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14, Σ13

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (4 53 4

    ):::::::

    Σ14, Σ13

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (4 53 4

    ):::::::

    Σ14, Σ13

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (4 53 4

    ):::::::

    Σ14, Σ13

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (4 54 5

    ):::::::

    Σ14, Σ13

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (4 54 5

    ):::::::

    Σ14, Σ13

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (4 55 5

    ):::::::

    Σ14, Σ13

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (4 55 5

    ):::::::

    Σ14, Σ13

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (4 55 5

    ):::::::

    Σ14, Σ13

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (4 55 5

    ):::::::

    Σ14, Σ13

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (5 55 5

    ):::::::

    Σ14, Σ13

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (5 55 5

    ):::::::

    Σ14, Σ13

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)Σ12

    ::

    Σ14, Σ13

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (21

    )· (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14, Σ13, Σ

    12

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (21

    )Σ14, Σ

    13, Σ

    12

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ1τ2τ3τ4)

    (32

    )(τ1τ2τ3τ4)

    Σ14, Σ13, Σ

    12

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (43

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14, Σ13, Σ

    12

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    (43

    )Σ14, Σ

    13, Σ

    12

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ1τ2τ3τ4)

    (54

    )(τ1τ2τ3τ4)

    Σ14, Σ13, Σ

    12

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ1τ2τ3τ4)

    (54

    )(τ1τ2τ3τ4)

    Σ14, Σ13, Σ

    12

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ1τ2τ3τ4)

    (55

    )(τ1τ2τ3τ4)

    Σ14, Σ13, Σ

    12

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (55

    )(τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14, Σ13, Σ

    12

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (55

    )::::

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14, Σ13, Σ

    12

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    Σ11::

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)

    Σ14, Σ13, Σ

    12

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

  • . . . . . .

    Introduction and PreliminariesPre-fiber surface

    pseudo-fiber surface of level n

    (τ1τ2τ3τ4)(τ1τ2τ3τ4)Σ14, Σ

    13, Σ

    12, Σ

    11

    Yukari Funakoshi Unknotting operations for fibered knots and pseudo-fiber surfaces

    Introduction and PreliminariesPre-fiber surfacepseudo-fiber surface of level n