{ "id": "1310.2508", "version": "v5", "published": "2013-10-09T14:54:21.000Z", "updated": "2014-11-14T22:28:07.000Z", "title": "Cohomology of local systems on the moduli of principally polarized abelian surfaces", "authors": [ "Dan Petersen" ], "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", "categories": [ "math.NT", "math.AG" ], "abstract": "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.", "revisions": [ { "version": "v4", "updated": "2014-05-22T11:02:02.000Z", "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", "journal": null, "doi": null }, { "version": "v5", "updated": "2014-11-14T22:28:07.000Z" } ], "analyses": { "subjects": [ "11F46", "14K10", "11G18", "11F67", "11F75" ], "keywords": [ "principally polarized abelian surfaces", "local systems", "siegel cusp forms", "cohomology", "irreducible rational finite dimensional representation" ], "note": { "typesetting": "TeX", "pages": 18, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1310.2508P" } } }