We revisit Špakula's uniform K-homology, construct the external product for it and use this to deduce homotopy invariance of uniform K-homology.We define uniform K-theory and on manifolds of bounded geometry we give an interpretation of it via vector bundles of bounded geometry. We further construct a cap product with uniform K-homology and prove Poincaré duality between uniform K-theory and uniform K-homology on spin c manifolds of bounded geometry.
Uniform K-homologyIn this section we will investigate uniform K-homology-a version of K-homology that incorporates into its definition uniformity estimates that one usually has for, e.g., Dirac operators over manifolds of bounded geometry (see Example 2.7). Uniform K-homology was introduced by Špakula [Špa08, Špa09]. 2 We will revisit it and we will prove additional 1 Though note that this approach does not give a concrete formula for how to find this vector bundle. It is an important observation of Atiyah and Singer (and later elaborated upon by Baum and Douglas in their geometric picture for K-homology) that if the K-homology class is given by an elliptic pseudodifferential operator, then one can use the symbol of the operator to get a representative as the class of a twisted Dirac operator. 2 But we have changed the definition slightly, see Section 2.2 for how and why.