Many notions introduced in Riemannian geometry (in particular sectional curvature) can be generalized to metric spaces without relying on concepts such as differentiability. Although these notions are defined synthetically, they appear very naturally, when one studies convergence of Riemannian manifolds. On the other hand these spaces admitt a surprisingly rich structure, if studied as a class among themselves.
In this lecture we will study spaces admitting a (synthethical) sectional curvature bound together with a notion of convergence, the so called Gromov-Hausdorff convergence, and investigate the interplay of geometry and (algebraic) topological invariants.
In order to follow the lecture participants should have some background in Riemannian Geometry and Algebraic Topology.