proposition: Lemma coeff_mat_ext {m n : nat} (x0 : T) (v1 v2 : matrix m n) : v1 = v2 <-> forall i j, (coeff_mat x0 v1 i j) = (coeff_mat x0 v2 i j).
proof: Proof. split. by move => ->. intro H. now apply (coeff_mat_ext_aux x0 x0 v1 v2). Qed.
imports: Coq(Reals Psatz ssreflect) Rcomplements Rbar Markov Iter Lub