On the images of the Galois representations attached to genus 2 Siegel modular forms, by Luis V. Dieulefait

We address the problem of the determination of the images of the Galois representations attached to genus $2$ Siegel cusp forms of level $1$ having multiplicity one. These representations are symplectic. We prove that the images are as large as possible for almost every prime, if the Siegel cusp form is not a Maass spezialform and verifies two easy to check conditions.

Luis V. Dieulefait <luisd@mat.ub.es,luisd@math.univ-paris13.fr>