proposition: Lemma ex1_prop5 i j: gle rL i j -> sub (Vg Jf i) (psI (ex1_systemi j)).
proof: Proof. move => lij;rewrite - (ex1_prop5a (proj2 (ex1_prop2 lij))); exact:(HJm lij). Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)