Invited Talks -- Computing and Proving -- Rewriting for Deduction and Verification -- Regular Papers -- Universal Interaction Systems with Only Two Agents -- General Recursion on Second Order Term Algebras -- Beta Reduction Constraints -- From Higher-Order to First-Order Rewriting -- Combining Pattern E-Unification Algorithms -- Matching Power -- Dependency Pairs for Equational Rewriting -- Termination Proofs by Context-Dependent Interpretations -- Uniform Normalisation beyond Orthogonality -- Verifying Orientability of Rewrite Rules Using the Knuth-Bendix Order -- Relating Accumulative and Non-accumulative Functional Programs -- Context Unification and Traversal Equations -- Weakly Regular Relations and Applications -- On the Parallel Complexity of Tree Automata -- Transfinite Rewriting Semantics for Term Rewriting Systems -- Goal-Directed E-Unification -- The Unification Problem for Confluent Right-Ground Term Rewriting Systems -- On Termination of Higher-Order Rewriting -- Matching with Free Function Symbols — A Simple Extension of Matching? -- Deriving Focused Calculi for Transitive Relations -- A Formalised First-Order Con uence Proof for the ?-Calculus Using One-Sorted Variable Names (Barendregt Was Right after all ... almost) -- A Normal Form for Church-Rosser Language Systems -- Confluence and Termination of Simply Typed Term Rewriting Systems -- Parallel Evaluation of Interaction Nets with MPINE -- Stratego: A Language for Program Transformation Based on Rewriting Strategies System Description of Stratego 0.5.

This book constitutes the refereed proceedings of the 12th International Conference on Rewriting Techniques and Applications, RTA 2001, held in Utrecht, The Netherlands, in May 2001. The 23 revised full papers presented together with two system descriptions were carefully reviewed and selected from 55 submissions. All current aspects of rewriting are addressed.