Module Univ.Variance

type t =
| Irrelevant
| Covariant
| Invariant

A universe position in the instance given to a cumulative inductive can be the following. Note there is no Contravariant case because forall x : A, B <= forall x : A', B' requires A = A' as opposed to A' <= A.

val check_subtype : t -> t -> bool

check_subtype x y holds if variance y is also an instance of x

val sup : t -> t -> t
val pr : t -> Pp.t