Definition multi_and (xs: list expr): expr := fold_left andp xs truep.

(* Specifications: *)
Lemma multi_and_spec: forall (xs: list expr),
|-- multi_and xs <--> fold_right andp TT xs.
Lemma multi_and_multi_imp: forall (xs: list expr) (y: expr),
|-- (multi_and xs --> y) <--> (multi_imp xs y).