fact: Fixpoint invariant_algo m n p q := if m is m1.+1 then invariant_algo m1 n (left (m1 + n) p) (left_poly (2 ^ (m1 + n)) q) /\ invariant_algo m1 n (right (m1 + n) p) (right_poly (2 ^ (m1 + n)) q) else q = algo n p.
imports: mathcomp(all_ssreflect all_algebra ssrnum)