val add_lt_constraint: NCic.universe -> NCic.universe -> unit
val universe_eq: NCic.universe -> NCic.universe -> bool
val universe_leq: NCic.universe -> NCic.universe -> bool
val add_lt_constraint: NCic.universe -> NCic.universe -> unit
val universe_eq: NCic.universe -> NCic.universe -> bool
val universe_leq: NCic.universe -> NCic.universe -> bool