On the finiteness of the classifying space of diffeomorphisms of reducible three manifolds

Kontsevich ([Kir95, Problem 3.48]) conjectured that $\mathrm {BDiff}(M, \text {rel }\partial )$ has the homotopy type of a finite CW complex for all compact $3$ -manifolds with nonempty boundary. Hatcher-McCullough ([HM97]) proved this conjecture when M is irreducible. We prove a homolo...

Full description

Saved in:
Bibliographic Details
Main Author: Sam Nariman
Format: Article
Language:English
Published: Cambridge University Press 2025-01-01
Series:Forum of Mathematics, Sigma
Subjects:
Online Access:https://www.cambridge.org/core/product/identifier/S2050509425000386/type/journal_article
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Kontsevich ([Kir95, Problem 3.48]) conjectured that $\mathrm {BDiff}(M, \text {rel }\partial )$ has the homotopy type of a finite CW complex for all compact $3$ -manifolds with nonempty boundary. Hatcher-McCullough ([HM97]) proved this conjecture when M is irreducible. We prove a homological version of Kontsevich’s conjecture. More precisely, we show that $\mathrm {BDiff}(M, \text {rel }\partial )$ has finitely many nonzero homology groups each finitely generated when M is a connected sum of irreducible $3$ -manifolds that each have a nontrivial and non-spherical boundary.
ISSN:2050-5094