GUEST EDITOR'S FOREWORD
Sequences, Datalog, and Transducers
Safe Locking Policies for Dynamic Databases
Algebras for Querying Text Regions: Expressive Power and Optimization
Arity Bounds in First-Order Incremental Evaluation and Definition of Polynomial Time Database Queries
Increasing the Resilience of Distributed and Replicated Database Systems
Semantics and Expressiveness Issues in Active Databases
Learning with Refutation
Characterizing Multiterminal Flow Networks and Computing Flows in Networks of Small Treewidth
Approximating Hyper-Rectangles: Learning and Pseudorandom Sets
Achilles and the Tortoise Climbing Up the Arithmetical Hierarchy
A Three-Party Communication Problem
Author Index for Volume 57