Citation | Professor Casson is distinguished for his pioneering work in low dimensional topology. His two best known contributions are his invention of Casson handles for 4-manifolds (later used by Freedman to classify simply connected 4 dimensional manifolds), and his introduction of the Casson invariant, which was the first of a family of new invariants of 3-manifolds related to quantum field theory. Other important contributions include his joint discovery of the Casson-Gordon invariant in knot theory, his unpublished thesis on surgery and triangulations of topological manifolds, and his recent proof of an old conjecture about Seifert fibered manifolds. |