(* A boolean test for module isomorphism that is only valid for simple        *)
(* modules; this is the only case that matters in practice.                   *)

(* Specifications: *)
Lemma nz_row_mxsimple U : mxsimple U -> nz_row U != 0.
Lemma mxsimple_iso_simple U V :
mxsimple_iso U V -> mxsimple U -> mxsimple V.