Theorems for free! Page 1 Theorems for free! Philip Wadler University of Glasgow* Abstract
From the type of a polymorphic function we can derive a theorem that it satisfies. Every function …

We motivate the design of typed assembly language (TAL) and present a type-preserving
ttranslation from Systemn F to TAL. The typed assembly language we pressent is based on a …

We investigate the interactions of subty** and recursive types, in a simply typed λ-
calculus. The two fundamental questions here are whether two (recursive) types are in the …

First published in 1998, this textbook is a broad but rigourous survey of the theoretical basis
for the design, definition and implementation of programming languages and of systems for …

Bounded quantification was introduced by Cardelli and Wegner as a means of ty**
functions that operate uniformly over all subtypes of a given type. They defined a simple …

We introduce System FC, which extends System F with support for non-syntactic type
equality. There are two main extensions:(i) explicit witnesses for type equalities, and (ii) …

Traditional static type systems are very effective for verifying basic interface specifications,
but are somewhat limited in the kinds specifications they support. Dynamically-checked …

Pizza is a strict superset of Java that incorporates three ideas from the academic community:
parametric polymorphism, higher-order functions, and algebraic data types. Pizza is defined …

There is a standard syntax for Girard's linear logic, due to Abramsky, and a standard
semantics, due to Seely. Alas, the former is incoherent with the latter: different derivations of …

Traditional techniques for implementing polymorphism use a universal representation for
objects of unknown type. Often, this forces a compiler to use universal representations even …