Module of covariants

In algebra, given an algebraic group G, a G-module M and a G-algebra A, all over a field k, the module of covariants of type M is the $$A^G$$-module


 * $$(M \otimes_k A)^G.$$

where $$-^G$$ refers to taking the elements fixed by the action of G; thus, $$A^G$$ is the ring of invariants of A.