Home Mathematics The Atiyah–Patodi–Singer signature formula for measured foliations
Article
Licensed
Unlicensed Requires Authentication

The Atiyah–Patodi–Singer signature formula for measured foliations

Published/Copyright: March 7, 2013

Abstract

Given a compact manifold with boundary X0 endowed with a foliation 0 transverse to the boundary, and which admits a holonomy invariant transverse measure Λ, we define three types of signature for the pair (foliation, boundary foliation): the analytic signature, denoted by σΛ,an(X0,X0), is the leafwise L2-Λ-index of the signature operator on the extended manifold X obtained by attaching cylindrical ends to the boundary; the Hodge signature σΛ,Hodge(X0,X0) is defined using the natural representation of the Borel groupoid of X on the field of square integrable harmonic forms on the leaves; and the de Rham signature, σΛ,dR(X0,X0), defined using the natural representation of the Borel groupoid 0 of X0 on the field of the L2-relative de Rham spaces of the leaves. We prove that these three signatures coincide

σΛ,an(X0,X0)=σΛ,Hodge(X0,X0)=σΛ,dR(X0,X0).

As a consequence of the index formula we proved in [Bull. Sci. Math. (2010), DOI 10.1016/ j.bulsci.2010.10.003], we finally obtain the Atiyah–Patodi–Singer signature formula for measured foliations:

σΛ,dR(X0,X0)=L(T0),CΛ+1/2[ηΛ(D)].

The author wishes to thank Paolo Piazza for having suggested the problem and for a number of interesting discussions, Georges Skandalis, James Heitsch, Moulay T. Benameur, Sara Azzali, Eric Leichtnam, Stéphane Vassout and Yuri Kordyukov for discussions and comments. We heartily thank the referee for pointing out a wrong proof and suggesting the solution.

Received: 2012-11-20
Revised: 2012-12-10
Published Online: 2013-3-7
Published in Print: 2014-10-1

© 2014 by De Gruyter

Downloaded on 1.4.2026 from https://www.degruyterbrill.com/document/doi/10.1515/crelle-2012-0117/html
Scroll to top button