Sylvain Cappell

Who is Sylvain Cappell?

Sylvain Edward Cappell, a Belgian American mathematician and former student of William Browder at Princeton University, is a topologist who has spent most of his career at the Courant Institute of Mathematical Sciences at NYU, where he is now the Silver Professor of Mathematics.

He was born in Brussels, Belgium and immigrated with his parents to New York City in 1950 and grew up largely in this city. In 1963, as a senior at the Bronx High School of Science, he won first place in the Westinghouse Science Talent Search for his work on "The Theory of Semi-cyclical Groups with Special Reference to Non-Aristotelian Logic." He is best known for his "codimension one splitting theorem", which is a standard tool in high dimensional geometric topology, and a number of important results proven with his collaborator Julius Shaneson. Their work includes many results in knot theory and aspects of low-dimensional topology. They gave the first nontrivial examples of topological conjugacy of linear transformations, which led to a flowering of research on the topological study of spaces with singularities.