1.

Record Nr.

UNINA9910154744603321

Autore

Walker Kevin

Titolo

An Extension of Casson's Invariant. (AM-126), Volume 126 / / Kevin Walker

Pubbl/distr/stampa

Princeton, NJ : , : Princeton University Press, , [2016]

©1992

ISBN

1-4008-8246-X

Descrizione fisica

1 online resource (140 pages) : illustrations

Collana

Annals of Mathematics Studies ; ; 308

Classificazione

SK 320

Disciplina

514/.3

Soggetti

Three-manifolds (Topology)

Invariants

Lingua di pubblicazione

Inglese

Formato

Materiale a stampa

Livello bibliografico

Monografia

Nota di bibliografia

Includes bibliographical references.

Nota di contenuto

Frontmatter -- Contents -- 0. Introduction -- 1. Topology of Representation Spaces -- 2. Definition of λ -- 3. Various Properties of λ -- 4. The Dehn Surgery Formula -- 5. Combinatorial Definition of λ -- 6. Consequences of the Dehn Surgery Formula -- A. Dedekind Sums -- B. Alexander Polynomials -- Bibliography

Sommario/riassunto

This book describes an invariant, l, of oriented rational homology 3-spheres which is a generalization of work of Andrew Casson in the integer homology sphere case. Let R(X) denote the space of conjugacy classes of representations of p(X) into SU(2). Let (W,W,F) be a Heegaard splitting of a rational homology sphere M. Then l(M) is declared to be an appropriately defined intersection number of R(W) and R(W) inside R(F). The definition of this intersection number is a delicate task, as the spaces involved have singularities. A formula describing how l transforms under Dehn surgery is proved. The formula involves Alexander polynomials and Dedekind sums, and can be used to give a rather elementary proof of the existence of l. It is also shown that when M is a Z-homology sphere, l(M) determines the Rochlin invariant of M.