val apply_subst_metasenv : substitution -> Cic.metasenv -> Cic.metasenv
val ppsubst : ?names:(Cic.name option list) -> substitution -> string
val buildsubst :
val apply_subst_metasenv : substitution -> Cic.metasenv -> Cic.metasenv
val ppsubst : ?names:(Cic.name option list) -> substitution -> string
val buildsubst :