Invited Contributions -- Intruder Theories (Ongoing Work) -- Theories for the Global Ubiquitous Computer -- Contributed Papers -- Choice in Dynamic Linking -- Soft lambda-Calculus: A Language for Polynomial Time Computation -- On the Existence of an Effective and Complete Inference System for Cryptographic Protocols -- Hypergraphs and Degrees of Parallelism: A Completeness Result -- Behavioral and Spatial Observations in a Logic for the ?-Calculus -- Election and Local Computations on Edges -- Decidability of Freshness, Undecidability of Revelation -- LTL over Integer Periodicity Constraints -- Unifying Recursive and Co-recursive Definitions in Sheaf Categories -- Deriving Bisimulation Congruences in the DPO Approach to Graph Rewriting -- A Denotational Account of Untyped Normalization by Evaluation -- On Finite Alphabets and Infinite Bases: From Ready Pairs to Possible Worlds -- Specifying and Verifying Partial Order Properties Using Template MSCs -- Angelic Semantics of Fine-Grained Concurrency -- On the Expressiveness of Infinite Behavior and Name Scoping in Process Calculi -- safeDpi: A Language for Controlling Mobile Code -- Distance Desert Automata and the Star Height One Problem -- Adhesive Categories -- A Game Semantics of Local Names and Good Variables -- Partial Correctness Assertions Provable in Dynamic Logics -- Polynomials for Proving Termination of Context-Sensitive Rewriting -- Bisimulation on Speed: Lower Time Bounds -- On Recognizable Timed Languages -- Tree Transducers and Tree Compressions -- On Term Rewriting Systems Having a Rational Derivation -- Duality for Labelled Markov Processes -- Electoral Systems in Ambient Calculi -- Strong Normalization of -Calculus with Explicit Substitutions -- Canonical Models for Computational Effects -- Reasoning about Dynamic Policies -- Probabilistic Bisimulation and Equivalence for Security Analysis of Network Protocols -- Strong Bisimulation for the Explicit Fusion Calculus -- Perfect-Information Stochastic Parity Games -- A Note on the Perfect Encryption Assumption in a Process Calculus.

ETAPS 2004 was the seventh instance of the European Joint Conferences on Theory and Practice of Software. ETAPS is an annual federated conference that was established in 1998 by combining a number of existing and new conferences. This year it comprised ?ve conferences (FOSSACS, FASE, ESOP, CC, TACAS), 23 satellite workshops, 1 tutorial, and 7 invited lectures (not including those that are speci?c to the satellite events). The events that comprise ETAPS address various aspects of the system - velopment process, including speci?cation, design, implementation, analysis and improvement. The languages, methodologies and tools that support these - tivities are all well within its scope. Di?erent blends of theory and practice are represented, with an inclination towards theory with a practical motivation on the one hand and soundly based practice on the other. Many of the issues inv- ved in software design apply to systems in general, including hardware systems, and the emphasis on software is not intended to be exclusive.