proposition: Lemma matchpg_size et bs w : matchpg bs et w -> size w = size et.
proof: Proof. elim: et bs w => [|e et IHet] bs [|s w] etMw //=; congr _.+1; case: s etMw. - by case: e (IHet ((if cbit0 e then Bpush1 else Bpush0) bs) w). - by case: e (IHet bs w). - by case: e bs => [] [|bs|bs] // /IHet. by case: e bs => [] [|bs|bs] // /IHet. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype) fourcolor(color)