Four-valued diagnoses for stratified knowledge-bases.- Fast cut-elimination by projection.- On the subject reduction property for algebraic type systems.- Presheaf models for concurrency.- Directed virtual reductions.- Bounded-variable fixpoint queries are PSPACE-complete.- Graph rewriting semantics for functional programming languages.- An extension of models of Axiomatic Domain Theory to models of Synthetic Domain Theory.- Relative undecidability in term rewriting.- Extending models of second order predicate logic to models of second order dependent type theory.- Eta-expansions in F ?.- Cut-free display calculi for relation algebras.- Computational aspects of arity hierarchies.- Weak semantics based on lighted button pressing experiments.- Kleene algebra with tests: Completeness and decidability.- Monadic NP and built-in trees.- Coercive subtyping in type theory.- Proofs in system F ? can be done in system F ? 1 .- Optimization problems with approximation schemes.- Computational representations of herbrand models using grammars.- Exact pairs for abstract bounded reducibilities.- The logic of explicitly presentation-invariant circuits.- Social confluence in client-server systems.- A type-free resource-aware ?-calculus.- Inductive definitions with decidable atomic formulas.- Call-by-Value, call-by-name and the logic of values.- On Cartesian monoids.- New intuitionistic logical constants: Undecidability of the conservativeness problem.