John Harvey, Swansea University

Title: Positively curved Riemannian 4-orbifolds with circle actions

Abstract: Positively curved Riemannian orbifolds of dimension 4
with an isometric circle action are classified up to equivariant
homeomorphism in joint work with Catherine Searle. A problem of
equivariant comparison geometry will be discussed which, if resolved,
would extend this result to Alexandrov geometry.