Critical values of automorphic L-functions for GL(r)×GL(r)

 We compute, up to an element of a fixed number field, the critical values of the L-function of a pair of automorphic, cuspidal, cohomological representations of any GL(r). The result is expressed as a product of cohomological periods divided by an archimedean integral. The main tool used is the rationality of the cohomology of the three representations involved in the Rankin–Selberg integral. As an intermediate step, we also obtained the rationality of the Eisenstein cohomology.