An equivariant Atiyah-Patodi-Singer index theorem for proper actions I: the index formula

Peter Hochs, Bai-Ling Wang, Hang Wang

Consider a proper, isometric action by a unimodular locally compact group $G$ on a Riemannian manifold $M$ with boundary, such that $M/G$ is compact. For an equivariant, elliptic o…