Equivariant Enumerative Geometry
Classical enumerative geometry asks geometric questions of the form "how many?" and expects an integral answer. For example, how many circles can we draw tangent to a given three? How many lines lie on a cubic surface? The fact that these answers are well-defined integers, independent upon the initial parameters of the problem, is Schubert’s principle of conservation of number. A modern perspective might argue that conservation of number is a shadow cast by the presence of homotopy theory. Abstract enumerative geometry can be roughly thought of as asking for strictly richer answers than integers, and we might expect to encounter such abstraction wherever homotopy theory lives. In this talk we will outline a program of "equivariant enumerative geometry", which wields equivariant homotopy theory to explore enumerative questions in the presence of symmetry.