Hodge cycles and the Leray filtration (2103.05038v2)

Abstract: This is loosely a continuation of the author's previous paper arXiv:1802.09496. In the first part, given a fibered variety, we pull back the Leray filtration to the Chow group, and use this to give some criteria for the Hodge and Tate conjectures to hold for such varieties. In the second part, we show that the Hodge conjecture holds for a good desingularization of a self fibre product of a non-isotrivial elliptic surface under appropriate conditions. We also show that the Hodge and Tate conjectures hold for natural families of abelian varieties parameterized by certain Shimura curves. This uses Zucker's description of the mixed Hodge structure on the cohomology of a variation of Hodge structures on a curve, along with appropriate "vanishing" theorems.