val subst_vars :
Cic.term Cic.explicit_named_substitution -> Cic.term -> Cic.term
-(* ?????????? *)
+(* TODO CSC rename to subst_meta *)
+
+(* lift_meta [t_1 ; ... ; t_n] t *)
+(* returns the term [t] where [Rel i] is substituted with [t_i] *)
+(* [t_i] is lifted as usual when it crosses an abstraction *)
val lift_meta : (Cic.term option) list -> Cic.term -> Cic.term
+