Explicit Chow-Lefschetz Decomposition for Kummer manifolds

Abstract

Let X be the quotient of a smooth projective variety over a field by a finite group action (in which case we say X is pseudo-smooth), such that the singularities of X are isolated k-rational points. Let Y be obtained by blowing up these points on X. Assume further that Y is pseudo-smooth, and that the components of the exceptional divisor are projective spaces. Then, without invoking the theory of finite-dimensional motives or assuming any of the standard conjectures, we show that a Chow-Kunneth decomposition on either X or Y gives rise, by means of an explicit construction, to a Chow-Kunneth decomposition on the other. We use these constructions to show that various properties (among them, Conjectures of Murre, and being of Lefschetz type) hold for X if and only if they hold for Y. The main examples of interest to us are Kummer manifolds. We give several further applications of our construction to this particular class of examples.