Fr ́echet Lie Algebroids and TheirCohomology

We define Lie and Courant algebroids on Fr ́echetmanifolds. Moreover, we construct a Dirac structure on the gen-eralized tangent bundle of a Fr ́echet manifold and show that itinherits a Fr ́echet Lie algebroid structure. We show that the Liealgebroid cohomology of theB-cotangent bundle Lie algebroidof a weakly symplectic Fr ́echet manifoldMis the Lichnerowicz-Poisson cohomology ofM