Cohomology of local systems on the moduli of principally polarized abelian surfaces

Autor: Dan Petersen
Rok vydání: 2015
Předmět:
Zdroj: Pacific Journal of Mathematics. 275:39-61
ISSN: 0030-8730
DOI: 10.2140/pjm.2015.275.39
Popis: Let A_2 be the moduli stack of principally polarized abelian surfaces and V a smooth l-adic sheaf on A_2 associated to an irreducible rational finite dimensional representation of Sp(4). We give an explicit expression for the cohomology of V in any degree in terms of Tate type classes and Galois representations attached to elliptic and Siegel cusp forms. This confirms a conjecture of Faber and van der Geer. As an application we prove a dimension formula for vector-valued Siegel cusp forms for Sp(4,Z) of weight three, which had been conjectured by Ibukiyama.
Comment: 18 pages. v3: Added a proof of a dimension formula for vector-valued Siegel cusp forms for Sp(4,Z) of weight three, previously conjectured by Ibukiyama. v4: Many minor changes and improvements. Final version, to appear in Pacific Journal of Mathematics
Databáze: OpenAIRE