Congruences automorphes et torsion dans la cohomologie d'un syst\`eme   local d'Harris-Taylor
  The principal aim of this paper is to construct torsion cohomology classes in the initial terms of a spectral sequence computing the cohomology of a Kottwitz-Harris-Taylor Shimura variety. Beside we produce some global congruences between automorphic representations. 
Pascal Boyer
math.NT