:< package:compdata

type f :< g = (Proj (ComprEmb (Elem f g)) f g)
compdata Data.Comp.Multi.Projection Data.Comp.Projection
The constraint e :< p expresses that e is a component of the type p. That is, p is formed by binary products using the type e. The occurrence of e must be unique. For example we have Int :< (Bool,(Int,Bool)) but not Bool :< (Bool,(Int,Bool)).
type f :<: g = (Subsume (ComprEmb (Elem f g)) f g)
compdata Data.Comp.Multi.Ops Data.Comp.Multi.Sum Data.Comp.Ops Data.Comp.Sum
A constraint f :<: g expresses that the signature f is subsumed by g, i.e. f can be used to construct elements in g.