(** * Semantics of combinators *)

(* Specifications: *)
(* begin semReturn *)
Lemma semReturn {A} (x : A) : semGen (returnGen x) <--> [set x].
(* end semReturn *)
(* begin semReturnSize *)
Lemma semReturnSize A (x : A) (s : nat) :
semGenSize (returnGen x) s <--> [set x].