Additional data types related to ordering notions
data Trichotomous : (a -> a -> Type) -> (a -> a -> Type) -> (a -> a -> Type) -> a -> a -> Type
Trichotomous formalises the fact that three relations are mutually exclusive.
It is meant to be used with relations that complement each other so that the
`Trichotomous lt eq gt` relation is the total relation.
MkLT : lt v w -> Not (eq v w) -> Not (gt v w) -> Trichotomous lt eq gt v w
MkEQ : Not (lt v w) -> eq v w -> Not (gt v w) -> Trichotomous lt eq gt v w
MkGT : Not (lt v w) -> Not (eq v w) -> gt v w -> Trichotomous lt eq gt v w