proposition: Lemma trmx_llsub : (llsubmx A)^T === ursubmx A^T.
proof: Proof. by move => i j /=; reflexivity. Qed.
imports: ssreflect ssrbool ssrfun eqtype ssrnat seq choice fintype finfun bigops ssralg groups perm zmodp morphisms Ring RingClass bigopsClass Setoid Morphisms