Definition Mdo {A B:Type} (ma:monad A) (mb:monad B) := ma >>= (λ _, mb).Infix ">>" := Mdo (at level 15, left associativity) : monad_scope.

Lemma mono_mono_Mdo_mono {A B:Type} (ma:monad A) (mb:monad B): Mmono ma → (Mmono mb) → Mmono (ma >> mb).