(* Simultaneous evaluation of a list of expressions *)
Fixpoint list_eval (es:list expr) (vs:list val) : pred world :=
match es, vs with
| e::es', v::vs' => eval e v && list_eval es' vs'
| nil, nil => TT
| _, _ => FF
end.

Lemma list_eval_evaluate_exprs : forall es vs w,
list_eval es vs w ->
evaluate_exprs (fst (snd w)) es vs.