Communicating contexts: A pragmatic approach to information exchange -- A short and flexible proof of strong normalization for the calculus of constructions -- Codifying guarded definitions with recursive schemes -- The metatheory of UTT -- A user's friendly syntax to define recursive functions as typed ?-terms -- I/O automata in Isabelle/HOL -- A concrete final coalgebra theorem for ZF set theory -- On extensibility of proof checkers -- Syntactic categories in the language of mathematics -- Formalization of a ?-calculus with explicit substitutions in Coq.

This book presents a strictly refereed collection of revised full papers selected from the papers accepted for the TYPES '94 Workshop, held under the auspices of the ESPRIT Basic Research Action 6453 Types for Proofs and Programs in Bastad, Sweden, in June 1994. The 10 papers included address various aspects of developing computer-assisted proofs and programs using a logical framework. Type theory and three logical frameworks based on it are dealt with: ALF, Coq, and LEGO; other topics covered are metatheory, the Isabelle system, 2-calculus, proof checkers, and ZF set theory.