On the intersection motive of certain Shimura varieties: the case of Siegel threefolds
arXiv:1706.02743 · doi:10.2140/akt.2019.4.525
Abstract
In this article, we construct a Hecke-equivariant Chow motive whose realizations equal intersection cohomology of Siegel threefolds with regular algebraic coefficients. As a consequence, we are able to define Grothendieck motives for Siegel modular forms.
36 pages; accepted for publication in Annals of K-Theory. Following remarks of the referee, the proof of Cor. 1.13 is now more detailed