The expressive power of transitive closure and 2-way multihead automata -- Correctness proof for the WAM with types -- Model checking of persistent Petri nets -- Provability in TBLL: A decision procedure -- How to implement first order formulas in local memory machine models -- A new approach to abstract data types II computation on ADTs as ordinary computation -- A primitive recursive set theory and AFA: On the logical complexity of the largest bisimulation -- On bounded theories -- The cutting plane proof system with bounded degree of falsity -- Denotational versus declarative semantics for functional programming -- On transitive closure logic -- Some aspects of the probabilistic behavior of variants of resolution -- Safe queries in relational databases with functions -- Logical inference and polyhedral projection -- Stable logic -- A transformational methodology for proving termination of logic programs -- Plausibility logic -- Towards Kleene Algebra with recursion -- Equational specification of abstract types and combinators -- Normal forms in infinite-valued logic: The case of one variable -- A fragment of first order logic adequate for observation equivalence -- Ordinal processes in comparative concurrency semantics -- Logical semantics of modularisation -- A cut-elimination procedure designed for evaluating proofs as programs -- Minimal from classical proofs -- Quantifier hierarchies over word relations -- Complexity results for the default- and the autoepistemic logic -- On Completeness for NP via projection translations -- Control of ?-automata, Church's problem, and the emptiness problem for tree ?-automata -- Comparing the theory of representations and constructive mathematics -- Infinitary queries and their asymptotic probabilities I: Properties definable in transitive closure logic -- On completeness of program synthesis systems -- Proving termination for term rewriting systems.

This volume presents the proceedings of the workshop CSL '91 (Computer Science Logic) held at the University of Berne, Switzerland, October 7-11, 1991. This was the fifth in a series of annual workshops on computer sciencelogic (the first four are recorded in LNCS volumes 329, 385, 440, and 533). The volume contains 33 invited and selected papers on a variety of logical topics in computer science, including abstract datatypes, bounded theories, complexity results, cut elimination, denotational semantics, infinitary queries, Kleene algebra with recursion, minimal proofs, normal forms in infinite-valued logic, ordinal processes, persistent Petri nets, plausibility logic, program synthesis systems, quantifier hierarchies, semantics of modularization, stable logic, term rewriting systems, termination of logic programs, transitive closure logic, variants of resolution, and many others.