FoSSaCS 2010 Invited Talk -- to Decidability of Higher-Order Matching -- Semantics of Programming Languages -- A Semantic Foundation for Hidden State -- Linearly-Used Continuations in the Enriched Effect Calculus -- Block Structure vs. Scope Extrusion: Between Innocence and Omniscience -- Completeness for Algebraic Theories of Local State -- Probabilistic and Randomised Computation -- Fair Adversaries and Randomization in Two-Player Games -- Retaining the Probabilities in Probabilistic Testing Theory -- Concurrency and Process Theory -- Forward Analysis of Depth-Bounded Processes -- Incremental Pattern-Based Coinduction for Process Algebra and Its Isabelle Formalization -- Parameterised Multiparty Session Types -- On the Relationship between Spatial Logics and Behavioral Simulations -- Modal and Temporal Logics -- An Easy Completeness Proof for the Modal ?-Calculus on Finite Trees -- When Model-Checking Freeze LTL over Counter Machines Becomes Decidable -- Model Checking Is Static Analysis of Modal Logic -- Counting CTL -- Algorithmic Metatheorems for Decidable LTL Model Checking over Infinite Systems -- Verification -- Toward a Compositional Theory of Leftist Grammars and Transformations -- Degrees of Lookahead in Regular Infinite Games -- Reachability Analysis of Communicating Pushdown Systems -- The Complexity of Synchronous Notions of Information Flow Security -- Categorical and Coalgebraic Methods -- Monads Need Not Be Endofunctors -- CIA Structures and the Semantics of Recursion -- Coalgebraic Correspondence Theory -- Lambda Calculus and Types -- Untyped Recursion Schemes and Infinite Intersection Types -- Solvability in Resource Lambda-Calculus -- A Hierarchy for Delimited Continuations in Call-by-Name.

This book constitutes the refereed proceedings of the 13th International Conference on Foundations of Software Science and Computational Structures, FOSSACS 2010, held in Paphos, Cyprus, in March 2010, as part of ETAPS 2010, the European Joint Conferences on Theory and Practice of Software. The 25 revised full papers presented together with the abstract of the keynote lecture were carefully reviewed and selected from 86 full paper submissions. The papers are organized in topical sections on semantics of programming languages, probabilistic and randomised computation, concurrency and process theory, modal and temporal logics, verification, categorical and coalgebraic methods, as well as lambda calculus and types.