3 papers
math.NT2013
On higher congruences between automorphic forms
Tobias Berger, Krzysztof Klosin, Kenneth Kramer
We prove a commutative algebra result which has consequences for congruences between automorphic forms modulo prime powers. If C denotes the congruence module for a fixed automorph…
math.NT2011
On deformation rings of residually reducible Galois representations and R=T theorems
Tobias Berger, Krzysztof Klosin
We study the crystalline universal deformation ring R (and its ideal of reducibility I) of a mod p Galois representation rho_0 of dimension n whose semisimplification is the direct…
math.NT2009
Arithmetic properties of similitude theta lifts from orthogonal to symplectic groups
Tobias Berger
By adapting the work of Kudla and Millson we obtain a lifting of cuspidal cohomology classes for the symmetric space associated to GO(V) for an indefinite rational quadratic space…