Section WT_FIND_LABEL.
Scheme wt_stmt_ind2 := Minimality for wt_stmt Sort Prop
with wt_lblstmts2_ind2 := Minimality for wt_lblstmts Sort Prop.
End WT_FIND_LABEL.

Theorem preservation:
forall S t S', step ge S t S' -> wt_state S -> wt_state S'.