%0 Journal Article %T The Chow ring of a K3 surface %A Arnaud Beauville %A Claire Voisin %J Mathematics %D 2001 %I arXiv %X Let X be a K3 surface. We show that the Chow group CH_0(X) of 0-cycles contains a "fundamental class" c_X of degree 1 with remarkable properties: any product of divisors is proportional to this class, and so is the second Chern class c_2(X). This preprint supersedes the preprint math.AG/0109063 by the first author, where the latter property was conjectured. %U http://arxiv.org/abs/math/0111146v1