(* Completely reducible modules, and Maeschke's Theorem. *)
Definition mx_completely_reducible V :=
forall U, mxmodule U -> (U <= V)%MS -> mxsplits V U.

Lemma mxsemisimpleS U V :
mxmodule U -> (U <= V)%MS -> mxsemisimple V -> mxsemisimple U.