Hint Resolve lexfg_env_t.

(* Specifications: *)
Theorem lexfg_env_s :
forall (a : terms) (s s' : sub_explicits),
e_lexfg _ (e_P1 ws) (e_P2 ws) s s' ->
e_lexfg _ (e_P1 wt) (e_P2 wt) (env a s) (env a s').