Skip to main content Accessibility help
×
Hostname: page-component-cd9895bd7-hc48f Total loading time: 0 Render date: 2024-12-23T15:45:08.506Z Has data issue: false hasContentIssue false

L2-Invariants from the algebraic point of view

Published online by Cambridge University Press:  07 September 2011

Wolfgang Lück
Affiliation:
Fachbereich Mathematik Universität Münster Einsteinstr. 62 48149 Münster Germany
Martin R. Bridson
Affiliation:
University of Oxford
Peter H. Kropholler
Affiliation:
University of Glasgow
Ian J. Leary
Affiliation:
Ohio State University
Get access

Summary

Abstract

We give a survey on L2-invariants such as L2-Betti numbers and L2-torsion taking an algebraic point of view. We discuss their basic definitions, properties and applications to problems arising in topology, geometry, group theory and K-theory.

Key words: dimensions theory over finite von Neumann algebras, L2-Betti numbers, Novikov Shubin invariants, L2-torsion, Atiyah Conjecture, Singer Conjecture, algebraic K-theory, geometric group theory, measure theory.

MSC 2000: 57S99, 46L99, 18G15, 19A99, 19B99, 20C07, 20F25.

Introduction

The purpose of this survey article is to present an algebraic approach to L2-invariants such as L2-Betti numbers and L2-torsion. Originally these were defined analytically in terms of heat kernels. Since it was discovered that they have simplicial and homological algebraic counterparts, there have been many applications to various problems in topology, geometry, group theory and algebraic K-theory, which on the first glance do not involve any L2-notions. Therefore it seems to be useful to give a quick and friendly introduction to these notions in particular for mathematicians who have a more algebraic than analytic background. This does not mean at all that the analytic aspects are less important, but for certain applications it is not necessary to know the analytic approach and it is possible and easier to focus on the algebraic aspects. Moreover, questions about L2-invariants of heat kernels such as the Atiyah Conjecture or the zero-in-the-spectrum-Conjecture turn out to be strongly related to algebraic questions about modules over group rings.

Type
Chapter
Information
Publisher: Cambridge University Press
Print publication year: 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Save book to Kindle

To save this book to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.

Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Available formats
×

Save book to Dropbox

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.

Available formats
×

Save book to Google Drive

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.

Available formats
×