End WT_FIND_LABEL.

(* Specifications: *)
Lemma preservation_estep:
forall S t S', estep ge S t S' -> wt_state S -> wt_state S'.
Lemma preservation_sstep:
forall S t S', sstep ge S t S' -> wt_state S -> wt_state S'.
Theorem preservation:
forall S t S', step ge S t S' -> wt_state S -> wt_state S'.
Theorem wt_initial_state:
forall S, initial_state prog S -> wt_state S.