-(* unwind_subst metasenv subst *)
-(* unwinds [subst] w.r.t. itself. *)
-(* It can restrict some metavariable in the [metasenv] *)
-val unwind_subst : Cic.metasenv -> substitution -> substitution * Cic.metasenv
-
-(* apply_subst subst t *)
-(* applies the substitution [subst] to [t] *)
-(* [subst] must be already unwinded *)
-val apply_subst : substitution -> Cic.term -> Cic.term
-
-(* apply_subst_reducing subst (Some (mtr,reductions_no)) t *)
-(* performs as (apply_subst subst t) until it finds an application of *)
-(* (META [mtr]) that, once unwinding is performed, creates a new *)
-(* beta-redex; in this case up to [reductions_no] consecutive *)
-(* beta-reductions are performed. *)
-(* Hint: this function is usually called when [reductions_no] *)
-(* eta-expansions have been performed and the head of the new *)
-(* application has been unified with (META [meta_to_reduce]): *)
-(* during the unwinding the eta-expansions are undone. *)
-(* [subst] must be already unwinded *)
-val apply_subst_reducing :
- substitution -> (int * int) option -> Cic.term -> Cic.term