Volume and Euler classes in bounded cohomology of transformation groups

Michael Brandenbursky, Michał Marcinkowski

Research output: Contribution to journalArticlepeer-review

Abstract

Let M be an oriented smooth manifold and Homeo(M, ω) the group of measure preserving homeomorphisms of M, where ω is a finite measure induced by a volume form. In this paper, we define volume and Euler classes in bounded cohomology of an infinite dimensional transformation group Homeo0(M, ω) and Homeo+(M, ω), respectively, and in several cases prove their non-triviality. More precisely, we define: • Volume classes in Hnb ( Homeo0(M, ω)), where M is a hyperbolic manifold of dimension n. • Euler classes in H2b ( Homeo+ (S, ω)), where S is an oriented closed hyperbolic surface. We show that Euler classes have positive norms for any closed hyperbolic surface and volume classes have positive norms for all hyperbolic surfaces and certain hyperbolic 3-manifolds; hence, they are non-trivial.

Original languageAmerican English
JournalGlasgow Mathematical Journal
DOIs
StateAccepted/In press - 1 Jan 2024

Keywords

  • bounded cohomology
  • characteristic classes
  • euler class
  • homeomomorphisms of manifolds
  • mapping class group
  • volume class

All Science Journal Classification (ASJC) codes

  • General Mathematics

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