Braids, Links, and Mapping Class Groups

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Braids, Links, and Mapping Class Groups
Braids, Links, and Mapping Class Groups.jpg
Author Joan Birman
SubjectBraid groups in low-dimensional topology
Publisher Princeton University Press
Publication date
1974
ISBN 978-0-691-08149-6

Braids, Links, and Mapping Class Groups is a mathematical monograph on braid groups and their applications in low-dimensional topology. It was written by Joan Birman, based on lecture notes by James W. Cannon, [1] and published in 1974 by the Princeton University Press and University of Tokyo Press, as volume 82 of the book series Annals of Mathematics Studies.

Contents

Although braid groups had been introduced in 1891 by Adolf Hurwitz and formalized in 1925 by Emil Artin, [1] this was the first book devoted to them. [2] It has been described as a "seminal work", [3] one that "laid the foundations for several new subfields in topology". [4]

Topics

Braids, Links, and Mapping Class Groups is organized into five chapters and an appendix. The first introductory chapter defines braid groups, configuration spaces, and the use of configuration spaces to define braid groups on arbitrary two-dimensional manifolds. It provides a solution to the word problem for braids, the question of determining whether two different-looking braid presentations really describe the same group element. It also describes the braid groups as automorphism groups of free groups and of multiply-punctured disks. [5]

The next three chapters present connections of braid groups to three different areas of mathematics. Chapter 2 concerns applications to knot theory, via Alexander's theorem that every knot or link can be formed by closing off a braid, and provides the first complete proof of the Markov theorem on equivalence of links formed in this way. It also includes material on the conjugacy problem, [5] important in this area because conjugate braids close off to form the same link, [1] and on the "algebraic link problem" (not to be confused with algebraic links) in which one must determine whether two links can be related to each other by finitely many moves of a certain type, equivalent to the homeomorphism of link complements. [2] Chapter 3 concerns representation theory, and includes Fox derivatives and Fox's free differential calculus, [1] the Magnus representation of free groups and the Gassner and Burau representations of braid groups. [5] Chapter 4 concerns the mapping class groups of 2-manifolds, Dehn twists and the Lickorish twist theorem, and plats, braids closed off in a different way than in Alexander's theorem. [5]

Chapter 5 is titled "plats and links". [1] It moves from 2-dimensional topology to 3-dimensional topology, and is more speculative, concerning connections between braid groups, 3-manifolds, and the classification of links. It includes also an analog of Alexander's theorem for plats, where the number of strands of the resulting plat turns out to be determined by the bridge number of a given link. [5] The appendix provides a list of 34 open problems. [1] [5] By the time Wilbur Whitten wrote his review, in June 1975, a handful of these had already been solved. [2]

Audience and reception

This is a book for advanced mathematics students and professionals, who are expected to already be familiar with algebraic topology and presentations of groups by generators and relators. Although it is not a textbook, it could possibly be used for graduate seminars. [1]

Reviewer Lee Neuwirth calls the book "most readable", "a nice mix of known results on the subject and new material". [5] Whitten describes it as "thorough, skillfully written" and "a pleasure to read". [2] Wilhelm Magnus finds it "remarkable" that while covering the subject with full mathematical rigor, Birman has preserved the intuitive appeal of some of its earliest works. [1]

Related Research Articles

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In mathematics, differential topology is the field dealing with the topological properties and smooth properties of smooth manifolds. In this sense differential topology is distinct from the closely related field of differential geometry, which concerns the geometric properties of smooth manifolds, including notions of size, distance, and rigid shape. By comparison differential topology is concerned with coarser properties, such as the number of holes in a manifold, its homotopy type, or the structure of its diffeomorphism group. Because many of these coarser properties may be captured algebraically, differential topology has strong links to algebraic topology.

<span class="mw-page-title-main">Topology</span> Branch of mathematics

In mathematics, topology concerns with the properties of a geometric object that are preserved under continuous deformations, such as stretching, twisting, crumpling, and bending; that is, without closing holes, opening holes, tearing, gluing, or passing through itself.

<span class="mw-page-title-main">Algebraic topology</span> Branch of mathematics

Algebraic topology is a branch of mathematics that uses tools from abstract algebra to study topological spaces. The basic goal is to find algebraic invariants that classify topological spaces up to homeomorphism, though usually most classify up to homotopy equivalence.

<span class="mw-page-title-main">Braid group</span> Group whose operation is a composition of braids

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<span class="mw-page-title-main">Low-dimensional topology</span>

In mathematics, low-dimensional topology is the branch of topology that studies manifolds, or more generally topological spaces, of four or fewer dimensions. Representative topics are the structure theory of 3-manifolds and 4-manifolds, knot theory, and braid groups. This can be regarded as a part of geometric topology. It may also be used to refer to the study of topological spaces of dimension 1, though this is more typically considered part of continuum theory.

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In mathematical knot theory, a link is a collection of knots which do not intersect, but which may be linked together. A knot can be described as a link with one component. Links and knots are studied in a branch of mathematics called knot theory. Implicit in this definition is that there is a trivial reference link, usually called the unlink, but the word is also sometimes used in context where there is no notion of a trivial link.

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The Joan & Joseph Birman Research Prize in Topology and Geometry was established in 2013 and is a prize given every other year by the Association for Women in Mathematics to an outstanding young female researcher in topology or geometry. The prize fund for the award was established by a donation from Joan Birman and her husband, Joseph Birman.

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References

  1. 1 2 3 4 5 6 7 8 Magnus, W. (January 1976), "Review of Braids, Links, and Mapping Class Groups", Bulletin of the American Mathematical Society , 82 (1): 42–46, doi: 10.1090/s0002-9904-1976-13937-7
  2. 1 2 3 4 Whitten, Wilbur, "Review of Braids, Links, and Mapping Class Groups", MathSciNet , MR   0375281
  3. Gilman, Jane; Menasco, William W.; Lin, Xiao-Song, eds. (2001), Knots, Braids, and Mapping Class Groups — Papers Dedicated to Joan S. Birman: Proceedings of a Conference on Low Dimensional Topology in Honor of Joan S. Birman's 70th Birthday, March 14-15, 1998, Columbia University, New York, New York, AMS/IP studies in advanced mathematics, American Mathematical Society, p. ix, ISBN   9780821829660
  4. Serenevy, Amanda Katharine (August 2006), Joan Birman and Topology (PDF), Mathematical Association of America, retrieved 2021-01-02
  5. 1 2 3 4 5 6 7 Neuwirth, L. P., "Review of Braids, Links, and Mapping Class Groups", zbMATH , Zbl   0305.57013