Equivariant cohomology over Lie groupoids and Lie-Rinehart algebras
Résumé
Using the language and terminology of relative homological algebra, in particular that of derived functors, we introduce equivariant cohomology over a general Lie-Rinehart algebra and equivariant de Rham cohomology over a locally trivial Lie groupoid in terms of suitably defined monads (also known as triples) and the associated standard constructions. This extends a characterization of equivariant de Rham cohomology in terms of derived functors developed earlier for the special case where the Lie groupoid is an ordinary Lie group, viewed as a Lie groupoid with a single object; in that theory over a Lie group, the ordinary Bott-Dupont-Shulman-Stasheff complex arises as an a posteriori object. We prove that, given a locally trivial Lie groupoid G and a smooth G-manifold f over the space B of objects of G, the resulting G-equivariant de Rham theory of f boils down to the ordinary equivariant de Rham theory of a vertex manifold relative to the corresponding vertex group, for any vertex in the space B of objects of G; this implies that the equivariant de Rham cohomology introduced here coincides with the stack de Rham cohomology of the associated transformation groupoid whence this stack de Rham cohomology can be characterized as a relative derived functor. We introduce a notion of cone on a Lie-Rinehart algebra and in particular that of cone on a Lie algebroid. This cone is an indispensable tool for the description of the requisite monads.
Mots clés
Lie groupoid
Lie algebroid
Atiyah sequence
Lie-Rinehart algebra
differentiable cohomology
Lie-Rinehart cohomology
Borel construction
equivariant cohomology
equivariant de Rham cohomology relative to a groupoid
equivariant cohomology relative to a Lie-Rinehart algebra
monad and dual standard construction
comonad and standard construction
relative derived functor
cone on a Lie-Rinehart algebra
cone on a Lie algebroid