arXiv subjects

Christian Johansson

Publications and source records attributed to Christian Johansson.

20 records · Page 2Linked to original sources

arXiv2013

A remark on a conjecture of Buzzard-Gee and the cohomology of Shimura varieties

We compare the conjecture of Buzzard-Gee on the association of Galois representations to C-algebraic automorphic representations with the conjectural description of the cohomology of Shimura varieties due to Kottwitz, and the reciprocity law at infinity due to Arthur. This is done by extending Langlands's representation of the L-group associated with a Shimura datum to a representation of the C-group of Buzzard-Gee. The approach offers an explanation of the explicit Tate twist appearing in Kottwitz's description.

math.NT↗

arXiv2013

Classicality for small slope overconvergent automorphic forms on some compact PEL Shimura varieties of type C

We study the rigid cohomology of the ordinary locus in some compact PEL Shimura varieties of type C with values in automorphic local systems and use it to prove a small slope criterion for classicality of overconvergent Hecke eigenforms. This generalises the work of Coleman, and is a first step in an ongoing project to extend the cohomological approach to classicality to higher-dimensional Shimura varieties.

math.NT↗