Primitive subtyping /\ implicit polymorphism |= object-orientation

François Bourdoncle, Stephan Merz
We present a new predicative and decidable type system, called ML< that adds primitive subtyping to the ML type system. Our goal is to devise a type discipline for a strongly typed, higher-order object-oriented language, building on well-understood concepts from type systems for functional languages, rather than on special calculi or resorting to "ad-hoc" polymorphism, second-order systems, or recursive types.
Available as:  gzip'ed Postscript 
  author = 	 "Fran{\c{c}}ois Bourdoncle and Stephan Merz",
  title = 	 "Primitive subtyping $\land$ implicit polymorphism
		  $\models$ object-orientation",
  editor =	 "Kim Bruce",
  booktitle =	 "Workshop on Foundations of Object-Oriented Languages ({FOOL3})",
  year =	 1996,
  month =	 jul

Stephan Merz