2006/03/20 by Maurizio Gabbrielli, Gabbrielli, Maurizio, Maria Chiara Meo +1
Computer Science · #Constraint Satisfaction and Optimization #FOS: Computer and information sciences #Logic, programming, and type systems #Model-Driven Software Engineering Techniques #Programming Languages (cs.PL) #cs.PL
paper · pdf · doi:10.48550/arxiv.cs/0603079
arxiv created 2006/03/20 · openalex publication_date 2006/03/20 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Constraint Handling Rules (CHR) are a committed-choice declarative language which has been designed for writing constraint solvers. A CHR program consists of multi-headed guarded rules which allow one to rewrite constraints into simpler ones until a solved form is reached. CHR has received a considerable attention, both from the practical and from the theoretical side. Nevertheless, due the use of multi-headed clauses, there are several aspects of the CHR semantics which have not been clarified yet. In particular, no compositional semantics for CHR has been defined so far. In this paper we introduce a fix-point semantics which characterizes the input/output behavior of a CHR program and which is and-compositional, that is, which allows to retrieve the semantics of a conjunctive query from the semantics of its components. Such a semantics can be used as a basis to define incremental and modular analysis and verification tools.