Feb 5:  Sylvain Cappell, CIMS

What kinds of invariants are used to classify spaces and their symmetries?
  

  We introduce kinds of invariants used to study and classify: 1) manifolds (in 3 levels of structure - differentiable, piecewise differentiable and topological); 2) more generally, varieties and their singularities; 3) the symmetries of all these, i.e., transformation groups which act on them.