Positive Scalar Curvature On Spin Pseudomanifolds: The Fundamental Group And Secondary Invariants

In this paper we continue the study of positive scalar curvature (psc) metrics on a depth-1 Thom-Mather stratified space M sigma with singular stratum beta M (a closed manifold of positive codimension) and associated link equal to L, a smooth compact manifold. We briefly call such spaces manifolds with L-fibered singularities. Under suitable spin assumptions we give necessary index-theoretic conditions for the existence of wedge metrics of positive scalar curvature. Assuming in addition that L is a simply connected homogeneous space of positive scalar curvature, L = G/H, with the semisimple compact Lie group G acting transitively on L by isometries, we investigate when these necessary conditions are also sufficient. Our main result is that our conditions are indeed sufficient for large classes of examples, even when M sigma and beta M are not simply connected. We also investigate the space of such psc metrics and show that it often splits into many cobordism classes.