Fact memv_submod_closed U : submod_closed U.
Canonical memv_opprPred U := OpprPred (memv_submod_closed U).
Canonical memv_addrPred U := AddrPred (memv_submod_closed U).
Canonical memv_zmodPred U := ZmodPred (memv_submod_closed U).
Canonical memv_submodPred U := SubmodPred (memv_submod_closed U).

Lemma memv_suml I r (P : pred I) vs U :
(forall i, P i -> vs i \in U) -> \sum_(i <- r | P i) vs i \in U.