←
equivalence relation
ideal
•
library
•
elements
• equivalence with hash
order
→
Equivalence relation with a corresponding hash function.
concept
equivalence with hash
[contravariant
value
element
]
subtypes
equivalence relation
[
element
]
integer
hash
(
element
the element
) pure
←
equivalence relation
ideal
•
library
•
elements
• equivalence with hash
order
→