New Geometric Splittings of Classical Knots and the Classification and Symmetries of Arborescent Knots

Total Page:16

File Type:pdf, Size:1020Kb

New Geometric Splittings of Classical Knots and the Classification and Symmetries of Arborescent Knots New Geometric Splittings of Classical Knots and the Classification and Symmetries of Arborescent Knots Francis Bonahon & Laurence C. Siebenmann Department of Mathematics Math´ematique, Bˆatiment 425 University of Southern California Universit´ede Paris-Sud LosAngeles,CA90089-2532,U.S.A. 91405OrsayCedex,France Version: January 26, 2016 Copyright: Francis Bonahon and Laurent Sienbenmann, 1979-2010 Preface to the 30-th year edition Dedicated to Jos´eMontesinos on the occasion of his 65-th birthday We began writing this monograph in 1979. It originally started as an article for the conference proceedings [BroT], but it soon developed into a book project of its own as the size of the manuscript was rapidly increasing. The two articles [BonS1] and [BonS2] both originated as appendices to this book, as did the unpublished part of the preprint [BonS3] that is dedicated to crystallographic groups. As time passed by, we eventually became bogged down in the process, in large part because of the overwhelming number of pictures and diagrams (about 640 in the current version) and because of the rapid changes in technology occurring at the same time. The book started as a camera-ready typescript with ink drawings, but we soon had to move to the new norm of TEX and computer drawn pictures. In particular, the book was used as developing ground for Sweet-TEX[Sie3], a TEX preprocessor for Macintosh computers created by the second author; this had the unfortunate outcome that many files became obsolete when Apple completely redesigned its operating system. The fact that the authors became geographically separated, and eventually drifted towards different scientific interests, did not help. By the late 1980s, we had collected the then-current state of the manuscript into an “official version”, that we made freely available by request. However, very few pictures were inserted in the text, it lacked bibliographic references, and it incorporated very different styles. By all accounts, it was pretty much unreadable to anybody but the authors. The next 20 years saw no change in the state of the manuscript, until recently. On the other hand, this work seems to have been reasonably influential. For instance, a quick Internet search returns about 100 articles and books referring to it (under many different titles!). We cannot help noting this fact with a certain satisfaction, in particular if one takes into account that these references point to an unpublished document that was difficult to access even as a preprint. Most of the theoretical results underpinning this work had appeared in [BonS1] in a very general form, but there clearly was a need for a precise description of their applications to knot theory, and of the algorithmic methods that we had developed. Combined with persistent exhortations from various colleagues and friends, this provided a strong incentive to resume the task of putting the text in a form suitable for publication. What follows is an extensively edited version of the text in its 1988 form. Many events have occurred in low-dimensional topology in the 30 years that have elapsed since we started this project, the most important one being the completion of the geometrisation program for 3–dimensional manifolds and orbifolds. With the corresponding hindsight and perspective, there are many parts that we would probably write in a very different way right now. However, we decided to preserve iii iv PREFACE TO THE 30-TH YEAR EDITION the historical data, and to remain faithful to the original. We limited our editing to locally improving the clarity of the exposition, and we respected some of the stylistic idiosyncrasies of the text. Updates and references to more recent work are indicated in footnotes. Several people have helped us with the technical aspects of the enterprise, in particular in the early years for typing and picture drawing. This includes Valerie Siviter, Bernadette Barbichon, Bernard Thomas and Banwari Lal Sharma. The majority of the pictures of the current version were drawn by Julien Roger. We are very grateful to all of them, as well as to Rob Kirby, Cameron Gordon and Andrew Ranicki for pushing us to prepare this edition. While preparing this revised version, the first author and Julien Roger were partially supported by the grant DMS-0604866 from the U.S. National Science Foundation. A large part of the mathematics in this book can be traced back to a series of lectures that Jos´eMontesinos gave at Orsay in the spring of 1976. In particular, the first author fondly remembers the many meetings that he had with Jos´ein the Jardin du Luxembourg in Paris, where Jos´esuggested as a possible research topic the classification of what we call here Montesinos knots. This became the dissertation [Bon1], and consequently launched the first author’s career as a mathematician (in addition to providing material for several chapters in this monograph). It is a pleasure to dedicate this book to Jos´eMontesinos as an acknowledgement of our debt, and as a way to celebrate his 65-th birthday and his many contributions to 3–dimensional topology. December 2009 Introduction I was led to the consideration of the forms of knots by Sir W. Thom- son’s1 Theory of Vortex Atoms, and consequently the point of view which at least at first I adopted was that of classifying knots by the number of their crossings. The subject is very much more difficult and intricate than at first sight one is inclined to think, and I feel that I have not suc- ceeded in catching the key-note. When that is found, the various results here given will, no doubt, appear in their real connection with one another, perhaps even as immediate consequences of a thoroughly adequate conception of the question. P.J. Tait [Tai1], 1877. A century after the Scottish physicist P.G. Tait wrote these words, it is still a challenging task for the topologists of this day to acquire a theoretical under- standing of knotting adequate to explain even the 630 or so (connected) knots tabulated in the last century by Tait, T.P. Kirkman and C.N. Little [Tai1, Tai2, Tai3, Kirk1, Kirk2, Lit1, Lit2, Lit3, Lit4]. These XIX-th century tabulations listed connected knots of 6 11 crossings excepting the 11 crossing connected knots hav- ing non-alternating projection. Since then, J.H. Conway [Conw] has tabulated the missing (non-alternating) 11 crossing connected knots plus the links of 6 10 cross- ings and very recently A. Caudron [Cau] has listed the 11 crossing links; concerning tabulations, see also [Has1, Has2]. This is the task that we shall attempt here, and accomplish in part. To Thom- son and Tait, our understanding would be disturbing inasmuch as it is more molec- ular than atomic; indeed the first phenomena we explain are described by integrally weighted trees a bit reminiscent of the organic molecule of the paraffin series. A knot K in the 3–sphere S3 = R3 ∪ {∞} is a collection of smoothly and disjointly embedded circles, namely K is a closed 1–submanifold of S3. Note that our terminology is somewhat non-standard, in the sense that we do not require knots to be connected, nor oriented. A link is a knot with > 2 components. Two 3 3 knots (S ,K1), (S ,K2) are isomorphic or “the same” if there is a degree +1 3 3 (namely orientation-preserving) diffeomorphism f : S → S with f(K1) = K2. Since a degree +1 diffeomorphism of S3 is isotopic to the identity [Cer], this is 3 equivalent to the property that K1 can be deformed to K2 in S by a smooth isotopy. In his remarkable heuristic work [Conw] on knot classification, J.H. Conway made much use of 2–spheres smoothly embedded in S3 and cutting K transversely in 4 points. We call these Conway spheres for the knot (S3,K). Figure 0.1 1= Lord Kelvin, or more precisely Baron Kelvin of Largs. See [Tho] v vi INTRODUCTION provides examples of such Conway spheres, obtained by capping off each of the dotted curves by one disk located in front of the sheet of paper and another disk in the back. Figure 0.1. 3 A knot (S ,K) is arborescent if there exists a finite collection F1,..., Fn of disjoint Conway spheres such that, if N is the closure of any component of 3 n S − i=1 Fi, then the pair (N,K ∩ N) takes the simple form of Figure 0.2 after suitableS isotopic deformation in S3. In this figure, N is S3 with the interior of a finite collection of disjoint balls deleted and K ∩ N is the intersection of N with two standard circles. Figure 0.2. For example the Conway spheres dotted in Figure 0.1 reveal that knot to be arborescent. In other words, arborescent knots are those that can be broken up into (almost) trivial pieces by Conway spheres. It was Conway who singled out this class and first studied their projections [Conw]. He found that over 75% of the knots tabulated in the XIX–th century, including nearly 90% of all knots and links of 6 10 crossings, are arborescent; see also [Cau]. These arborescent knots are called algebraic by Conway because, in the frame- work of [Conw], they are obtained from finitely many copies of the 1–crossing tan- gle by applying a sequence of “sum” and “product” operations; see Chapter 14. Unfortunately, the name of algebraic knot is also used to describe the iterated torus knots that occur as links of algebraic complex singularities; see for instance [Bra, Bur1, Bur2, Zar, EisN]. The two families have very little in common, in INTRODUCTION vii fact just the {2,n}{3, 4} and {3, 5} torus knots, as will be proved in Theorem A.8 in the Appendix.
Recommended publications
  • The Borromean Rings: a Video About the New IMU Logo
    The Borromean Rings: A Video about the New IMU Logo Charles Gunn and John M. Sullivan∗ Technische Universitat¨ Berlin Institut fur¨ Mathematik, MA 3–2 Str. des 17. Juni 136 10623 Berlin, Germany Email: {gunn,sullivan}@math.tu-berlin.de Abstract This paper describes our video The Borromean Rings: A new logo for the IMU, which was premiered at the opening ceremony of the last International Congress. The video explains some of the mathematics behind the logo of the In- ternational Mathematical Union, which is based on the tight configuration of the Borromean rings. This configuration has pyritohedral symmetry, so the video includes an exploration of this interesting symmetry group. Figure 1: The IMU logo depicts the tight config- Figure 2: A typical diagram for the Borromean uration of the Borromean rings. Its symmetry is rings uses three round circles, with alternating pyritohedral, as defined in Section 3. crossings. In the upper corners are diagrams for two other three-component Brunnian links. 1 The IMU Logo and the Borromean Rings In 2004, the International Mathematical Union (IMU), which had never had a logo, announced a competition to design one. The winning entry, shown in Figure 1, was designed by one of us (Sullivan) with help from Nancy Wrinkle. It depicts the Borromean rings, not in the usual diagram (Figure 2) but instead in their tight configuration, the shape they have when tied tight in thick rope. This IMU logo was unveiled at the opening ceremony of the International Congress of Mathematicians (ICM 2006) in Madrid. We were invited to produce a short video [10] about some of the mathematics behind the logo; it was shown at the opening and closing ceremonies, and can be viewed at www.isama.org/jms/Videos/imu/.
    [Show full text]
  • Notices of the American Mathematical Society
    OF THE AMERICAN MATHEMATICAL SOCIETY ISSU! NO. 116 OF THE AMERICAN MATHEMATICAL SOCIETY Edited by Everett Pitcher and Gordon L. Walker CONTENTS MEETINGS Calendar of Meetings ••••••••••••••••••••••••••••••••••.• 874 Program of the Meeting in Cambridge, Massachusetts •••.•.••••..•• 875 Abstracts for the Meeting- Pages 947-953 PRELIMINARY ANNOUNCEMENTS OF MEETINGS •••••••••••••••••.•• 878 AN APPEAL FOR PRESERVATION OF ARCHIVAL MATERIALS .•••••••••• 888 CAN MATHEMATICS BE SAVED? ••••••••••.••••••••..•.•••••••.. 89 0 DOCTORATES CONFERRED IN 1968-1969 ••••••••••••••.••••••.•••• 895 VISITING MATHEMATICIANS .•••••••••••••••••••••••••..•••••.. 925 ANNUAL SALARY SURVEY ••••••••••••.••••.••••.•.•.••••••.•• 933 PERSONAL ITEMS •••••••••••••••••••••••••••••...•••••••••• 936 MEMORANDA TO MEMBERS Audio Recordings of Mathematical Lectures ••••••••..•••••.•••.• 940 Travel Grants. International Congress of Mathematicians ••..•.•••••.• 940 Symposia Information Center ••••.•• o o • o ••••• o o •••• 0 •••••••• 940 Colloquium Lectures •••••••••••••••••••••••.• 0 ••••••••••• 941 Mathematical Sciences E'mployment Register .•.••••••..•. o • o ••••• 941 Retired Mathematicians ••••• 0 •••••••• 0 ••••••••••••••••• 0 •• 942 MOS Reprints .•••••• o •• o ••••••••••••••••••••••• o •••••• 942 NEWS ITEMS AND ANNOUNCEMENTS •••••. o •••••••••••••••• 877, 932, 943 ABSTRACTS PRESENTED TO THE SOCIETY •••••.••••.•.•.••..•..•• 947 RESERVATION FORM. o •••••••••••••••••••••••••••••••••••••• 1000 MEETINGS Calendar of Meetings NOTE: This Calendar lists all of the meetings which have
    [Show full text]
  • DEGREE-L MAPS INTO LENS SPACES and FREE CYCLIC ACTIONS on HOMOLOGY 3-SPHERES*
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Topology and its Applications 37 (1990) 131-136 131 North-Holland DEGREE-l MAPS INTO LENS SPACES AND FREE CYCLIC ACTIONS ON HOMOLOGY 3-SPHERES* E. LUST and D. SJERVE Department of Mathematics, The University of British Columbia, Vancouver, BC, Canada V6T 1 Y4 Received 20 September 1988 Revised 7 August 1989 If M is a closed orientable 3-manifold with H,(M) = Z,, then there is a lens space L,, unique up to homotopy, and a degree-l map f: A4+ L,,. As a corollary we prove that if 6 is a homology 3-sphere admitting a fixed point free action by Z,, then the regular covering fi + It?/??, is induced from the universal covering S3 --f L,,,, by a degree-l map f: 6/Z, + L,,,. AMS (MOS) Subj. Class.: Primary 57M99 homology 3-spheres degree-l maps lens spaces 1. Introduction In this paper we will be concerned with the existence of degree-l mapsf: M + L,, where M is a closed orientable 3-manifold and L,, is some lens space. If H,(M) = Z,, such maps exist and the lens space L,, is unique up to homotopy equivalence (see Theorem 3.4). If fi is a homology 3-sphere and p : A? -+ M is a regular covering with the cyclic group Z,, as its covering group, then H,(M) =Z,, and the covering p : A? + M is induced from the universal covering q : S3 -+ L,, by means of a degree-l map f: M + L,, (see Th eorem 3.5).
    [Show full text]
  • LEGENDRIAN LENS SPACE SURGERIES 3 Where the Ai ≥ 2 Are the Terms in the Negative Continued Fraction Expansion P 1 = A0 − =: [A0,...,Ak]
    LEGENDRIAN LENS SPACE SURGERIES HANSJORG¨ GEIGES AND SINEM ONARAN Abstract. We show that every tight contact structure on any of the lens spaces L(ns2 − s + 1,s2) with n ≥ 2, s ≥ 1, can be obtained by a single Legendrian surgery along a suitable Legendrian realisation of the negative torus knot T (s, −(sn − 1)) in the tight or an overtwisted contact structure on the 3-sphere. 1. Introduction A knot K in the 3-sphere S3 is said to admit a lens space surgery if, for some rational number r, the 3-manifold obtained by Dehn surgery along K with surgery coefficient r is a lens space. In [17] L. Moser showed that all torus knots admit lens space surgeries. More precisely, −(ab ± 1)-surgery along the negative torus knot T (a, −b) results in the lens space L(ab ± 1,a2), cf. [21]; for positive torus knots one takes the mirror of the knot and the surgery coefficient of opposite sign, resulting in a negatively oriented lens space. Contrary to what was conjectured by Moser, there are surgeries along other knots that produce lens spaces. The first example was due to J. Bailey and D. Rolfsen [1], who constructed the lens space L(23, 7) by integral surgery along an iterated cable knot. The question which knots admit lens space surgeries is still open and the subject of much current research. The fundamental result in this area is due to Culler– Gordon–Luecke–Shalen [2], proved as a corollary of their cyclic surgery theorem: if K is not a torus knot, then at most two surgery coefficients, which must be successive integers, can correspond to a lens space surgery.
    [Show full text]
  • Knots: a Handout for Mathcircles
    Knots: a handout for mathcircles Mladen Bestvina February 2003 1 Knots Informally, a knot is a knotted loop of string. You can create one easily enough in one of the following ways: • Take an extension cord, tie a knot in it, and then plug one end into the other. • Let your cat play with a ball of yarn for a while. Then find the two ends (good luck!) and tie them together. This is usually a very complicated knot. • Draw a diagram such as those pictured below. Such a diagram is a called a knot diagram or a knot projection. Trefoil and the figure 8 knot 1 The above two knots are the world's simplest knots. At the end of the handout you can see many more pictures of knots (from Robert Scharein's web site). The same picture contains many links as well. A link consists of several loops of string. Some links are so famous that they have names. For 2 2 3 example, 21 is the Hopf link, 51 is the Whitehead link, and 62 are the Bor- romean rings. They have the feature that individual strings (or components in mathematical parlance) are untangled (or unknotted) but you can't pull the strings apart without cutting. A bit of terminology: A crossing is a place where the knot crosses itself. The first number in knot's \name" is the number of crossings. Can you figure out the meaning of the other number(s)? 2 Reidemeister moves There are many knot diagrams representing the same knot. For example, both diagrams below represent the unknot.
    [Show full text]
  • Forming the Borromean Rings out of Polygonal Unknots
    Forming the Borromean Rings out of polygonal unknots Hugh Howards 1 Introduction The Borromean Rings in Figure 1 appear to be made out of circles, but a result of Freedman and Skora shows that this is an optical illusion (see [F] or [H]). The Borromean Rings are a special type of Brunninan Link: a link of n components is one which is not an unlink, but for which every sublink of n − 1 components is an unlink. There are an infinite number of distinct Brunnian links of n components for n ≥ 3, but the Borromean Rings are the most famous example. This fact that the Borromean Rings cannot be formed from circles often comes as a surprise, but then we come to the contrasting result that although it cannot be built out of circles, the Borromean Rings can be built out of convex curves, for example, one can form it from two circles and an ellipse. Although it is only one out of an infinite number of Brunnian links of three Figure 1: The Borromean Rings. 1 components, it is the only one which can be built out of convex compo- nents [H]. The convexity result is, in fact a bit stronger and shows that no 4 component Brunnian link can be made out of convex components and Davis generalizes this result to 5 components in [D]. While this shows it is in some sense hard to form most Brunnian links out of certain shapes, the Borromean Rings leave some flexibility. This leads to the question of what shapes can be used to form the Borromean Rings and the following surprising conjecture of Matthew Cook at the California Institute of Technology.
    [Show full text]
  • Hyperbolic Structures from Link Diagrams
    University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Doctoral Dissertations Graduate School 5-2012 Hyperbolic Structures from Link Diagrams Anastasiia Tsvietkova [email protected] Follow this and additional works at: https://trace.tennessee.edu/utk_graddiss Part of the Geometry and Topology Commons Recommended Citation Tsvietkova, Anastasiia, "Hyperbolic Structures from Link Diagrams. " PhD diss., University of Tennessee, 2012. https://trace.tennessee.edu/utk_graddiss/1361 This Dissertation is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a dissertation written by Anastasiia Tsvietkova entitled "Hyperbolic Structures from Link Diagrams." I have examined the final electronic copy of this dissertation for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Doctor of Philosophy, with a major in Mathematics. Morwen B. Thistlethwaite, Major Professor We have read this dissertation and recommend its acceptance: Conrad P. Plaut, James Conant, Michael Berry Accepted for the Council: Carolyn R. Hodges Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) Hyperbolic Structures from Link Diagrams A Dissertation Presented for the Doctor of Philosophy Degree The University of Tennessee, Knoxville Anastasiia Tsvietkova May 2012 Copyright ©2012 by Anastasiia Tsvietkova. All rights reserved. ii Acknowledgements I am deeply thankful to Morwen Thistlethwaite, whose thoughtful guidance and generous advice made this research possible.
    [Show full text]
  • Knots and Links in Lens Spaces
    Alma Mater Studiorum Università di Bologna Dottorato di Ricerca in MATEMATICA Ciclo XXVI Settore Concorsuale di afferenza: 01/A2 Settore Scientifico disciplinare: MAT/03 Knots and links in lens spaces Tesi di Dottorato presentata da: Enrico Manfredi Coordinatore Dottorato: Relatore: Prof.ssa Prof. Giovanna Citti Michele Mulazzani Esame Finale anno 2014 Contents Introduction 1 1 Representation of lens spaces 9 1.1 Basic definitions . 10 1.2 A lens model for lens spaces . 11 1.3 Quotient of S3 model . 12 1.4 Genus one Heegaard splitting model . 14 1.5 Dehn surgery model . 15 1.6 Results about lens spaces . 17 2 Links in lens spaces 19 2.1 General definitions . 19 2.2 Mixed link diagrams . 22 2.3 Band diagrams . 23 2.4 Grid diagrams . 25 3 Disk diagram and Reidemeister-type moves 29 3.1 Disk diagram . 30 3.2 Generalized Reidemeister moves . 32 3.3 Standard form of the disk diagram . 36 3.4 Connection with band diagram . 38 3.5 Connection with grid diagram . 42 4 Group of links in lens spaces via Wirtinger presentation 47 4.1 Group of the link . 48 i ii CONTENTS 4.2 First homology group . 52 4.3 Relevant examples . 54 5 Twisted Alexander polynomials for links in lens spaces 57 5.1 The computation of the twisted Alexander polynomials . 57 5.2 Properties of the twisted Alexander polynomials . 59 5.3 Connection with Reidemeister torsion . 61 6 Lifting links from lens spaces to the 3-sphere 65 6.1 Diagram for the lift via disk diagrams . 66 6.2 Diagram for the lift via band and grid diagrams .
    [Show full text]
  • Knots with Unknotting Number 1 and Essential Conway Spheres 1
    Algebraic & Geometric Topology 6 (2006) 2051–2116 2051 arXiv version: fonts, pagination and layout may vary from AGT published version Knots with unknotting number 1 and essential Conway spheres CMCAGORDON JOHN LUECKE For a knot K in S3 , let T(K) be the characteristic toric sub-orbifold of the orbifold (S3; K) as defined by Bonahon–Siebenmann. If K has unknotting number one, we show that an unknotting arc for K can always be found which is disjoint from T(K), unless either K is an EM–knot (of Eudave-Munoz)˜ or (S3; K) contains an EM– tangle after cutting along T(K). As a consequence, we describe exactly which large algebraic knots (ie, algebraic in the sense of Conway and containing an essential Conway sphere) have unknotting number one and give a practical procedure for deciding this (as well as determining an unknotting crossing). Among the knots up to 11 crossings in Conway’s table which are obviously large algebraic by virtue of their description in the Conway notation, we determine which have unknotting number one. Combined with the work of Ozsvath–Szab´ o,´ this determines the knots with 10 or fewer crossings that have unknotting number one. We show that an alternating, large algebraic knot with unknotting number one can always be unknotted in an alternating diagram. As part of the above work, we determine the hyperbolic knots in a solid torus which admit a non-integral, toroidal Dehn surgery. Finally, we show that having unknotting number one is invariant under mutation. 57N10; 57M25 1 Introduction Montesinos showed [24] that if a knot K has unknotting number 1 then its double branched cover M can be obtained by a half-integral Dehn surgery on some knot K∗ in S3 .
    [Show full text]
  • Absolutely Exotic Compact 4-Manifolds
    ABSOLUTELY EXOTIC COMPACT 4-MANIFOLDS 1 2 SELMAN AKBULUT AND DANIEL RUBERMAN Abstract. We show how to construct absolutely exotic smooth struc- tures on compact 4-manifolds with boundary, including contractible manifolds. In particular, we prove that any compact smooth 4-manifold W with boundary that admits a relatively exotic structure contains a pair of codimension-zero submanifolds homotopy equivalent to W that are absolutely exotic copies of each other. In this context, absolute means that the exotic structure is not relative to a particular parame- terization of the boundary. Our examples are constructed by modifying a relatively exotic manifold by adding an invertible homology cobor- dism along its boundary. Applying this technique to corks (contractible manifolds with a diffeomorphism of the boundary that does not extend to a diffeomorphism of the interior) gives examples of absolutely exotic smooth structures on contractible 4-manifolds. 1. Introduction One goal of 4-dimensional topology is to find exotic smooth structures on the simplest of closed 4-manifolds, such as S4 and CP2. Amongst mani- folds with boundary, there are very simple exotic structures coming from the phenomenon of corks, which are relatively exotic contractible mani- arXiv:1410.1461v3 [math.GT] 11 Dec 2014 folds discovered by the first-named author [2]. More specifically, a cork is a compact smooth contractible manifold W together with a diffeomor- phism f : ∂W → ∂W which does not extend to a self-diffeomorphism of W , although it does extend to a self-homeomorphism F : W → W . This gives an exotic smooth structure on W relative to its boundary, namely the pullback smooth structure by F.
    [Show full text]
  • Introduction to Vassiliev Knot Invariants First Draft. Comments
    Introduction to Vassiliev Knot Invariants First draft. Comments welcome. July 20, 2010 S. Chmutov S. Duzhin J. Mostovoy The Ohio State University, Mansfield Campus, 1680 Univer- sity Drive, Mansfield, OH 44906, USA E-mail address: [email protected] Steklov Institute of Mathematics, St. Petersburg Division, Fontanka 27, St. Petersburg, 191011, Russia E-mail address: [email protected] Departamento de Matematicas,´ CINVESTAV, Apartado Postal 14-740, C.P. 07000 Mexico,´ D.F. Mexico E-mail address: [email protected] Contents Preface 8 Part 1. Fundamentals Chapter 1. Knots and their relatives 15 1.1. Definitions and examples 15 § 1.2. Isotopy 16 § 1.3. Plane knot diagrams 19 § 1.4. Inverses and mirror images 21 § 1.5. Knot tables 23 § 1.6. Algebra of knots 25 § 1.7. Tangles, string links and braids 25 § 1.8. Variations 30 § Exercises 34 Chapter 2. Knot invariants 39 2.1. Definition and first examples 39 § 2.2. Linking number 40 § 2.3. Conway polynomial 43 § 2.4. Jones polynomial 45 § 2.5. Algebra of knot invariants 47 § 2.6. Quantum invariants 47 § 2.7. Two-variable link polynomials 55 § Exercises 62 3 4 Contents Chapter 3. Finite type invariants 69 3.1. Definition of Vassiliev invariants 69 § 3.2. Algebra of Vassiliev invariants 72 § 3.3. Vassiliev invariants of degrees 0, 1 and 2 76 § 3.4. Chord diagrams 78 § 3.5. Invariants of framed knots 80 § 3.6. Classical knot polynomials as Vassiliev invariants 82 § 3.7. Actuality tables 88 § 3.8. Vassiliev invariants of tangles 91 § Exercises 93 Chapter 4.
    [Show full text]
  • Monopole Floer Homology, Link Surgery, and Odd Khovanov Homology
    Monopole Floer Homology, Link Surgery, and Odd Khovanov Homology Jonathan Michael Bloom Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Graduate School of Arts and Sciences COLUMBIA UNIVERSITY 2011 c 2011 Jonathan Michael Bloom All Rights Reserved ABSTRACT Monopole Floer Homology, Link Surgery, and Odd Khovanov Homology Jonathan Michael Bloom We construct a link surgery spectral sequence for all versions of monopole Floer homology with mod 2 coefficients, generalizing the exact triangle. The spectral sequence begins with the monopole Floer homology of a hypercube of surgeries on a 3-manifold Y , and converges to the monopole Floer homology of Y itself. This allows one to realize the latter group as the homology of a complex over a combinatorial set of generators. Our construction relates the topology of link surgeries to the combinatorics of graph associahedra, leading to new inductive realizations of the latter. As an application, given a link L in the 3-sphere, we prove that the monopole Floer homology of the branched double-cover arises via a filtered perturbation of the differential on the reduced Khovanov complex of a diagram of L. The associated spectral sequence carries a filtration grading, as well as a mod 2 grading which interpolates between the delta grading on Khovanov homology and the mod 2 grading on Floer homology. Furthermore, the bigraded isomorphism class of the higher pages depends only on the Conway-mutation equivalence class of L. We constrain the existence of an integer bigrading by considering versions of the spectral sequence with non-trivial Uy action, and determine all monopole Floer groups of branched double-covers of links with thin Khovanov homology.
    [Show full text]