This paper continues our
project started in [J. Funct. Anal. 219, 109–133] where Poincaré duality in
K–theory was studied for singular manifolds with isolated conical singularities. Here,
we extend the study and the results to general stratified pseudomanifolds. We
review the axiomatic definition of a smooth stratification S of a topological
space X and we define a groupoid TSX, called the S–tangent space. This
groupoid is made of different pieces encoding the tangent spaces of strata, and
these pieces are glued into the smooth noncommutative groupoid TSX using
the familiar procedure introduced by Connes for the tangent groupoid of a
manifold. The main result is that C*(TSX) is Poincaré dual to C(X), in other
words, the S–tangent space plays the role in K–theory of a tangent space for
X.
Received: 20 February 2008
Revised: 18 August 2008
Accepted: 4 July 2008
Preview posted: 22 October 2008
Published: 1 January 2009
Proposed: Steve Ferry
Seconded: Ralph Cohen, Wolfgang Lueck