[TYPES] Parametricity with subtyping and a Top type
Tim.Sweeney at epicgames.com
Wed May 11 14:45:26 EDT 2005
Does subtyping and the existance of a Top type necessarily break
Parametricity guarantees that every function of type forall a.
a->a->Bool is a constant function. The same derivation appears
applicable to forall a. a->a->Top also, implying that it too must be
constant. But \x.\y.x and \x.\y.y are distinct functions inhabiting
forall a. a->a->Top.
What has gone wrong here?
Pierce's thesis touches on Top in F/\ but doesn't seem to address
Does there exist a systematic study of type system extensions known to
be compatible or incompatible with parametricity?
More information about the Types-list