Author: Lawrence C Paulson, Cambridge University Computer Laboratory
Copyright 1991 University of Cambridge
This is a version of Constructive Type Theory (extensional equality,
no universes).
Useful references on Constructive Type Theory:
B. Nordström, K. Petersson and J. M. Smith, Programming in Martin-Löf's
Type Theory (Oxford University Press, 1990)
Simon Thompson, Type Theory and Functional Programming (Addison-Wesley,
1991)