La correspondance de McKay
Abstract
Description
Let M be a quasiprojective algebraic manifold with K_M=0 and G a finite automorphism group of M acting trivially on the canonical class K_M; for example, a subgroup G of SL(n,C) acting on C^n in the obvious way. We aim to study the quotient variety X=M/G and its resolutions Y -> X (especially under the assumption that Y has K_Y=0) in terms of G-equivariant geometry of M. At present we know 4 or 5 quite different methods of doing this, taken from string theory, algebraic geometry, motives, moduli, derived categories, etc.
For G in SL(n,C) with n=2 or 3, we obtain several methods of cobbling together a basis of the homology of Y consisting of algebraic cycles in one-to-one correspondence with the conjugacy classes or the irreducible representations of G.
20 pages, uses Latex and bourbaki.cls. Séminaire Bourbaki, 52ème année, novembre 1999, no. 867, to appear in Astérisque 2000
20 pages, uses Latex and bourbaki.cls. Séminaire Bourbaki, 52ème année, novembre 1999, no. 867, to appear in Astérisque 2000