We survey recent results on the broad family of problems that can be cast as valued constraint satisfaction problems. We discuss general methods for analysing the complexity of such problems, give examples of tractable cases, and identify general features of the complexity landscape.

Most of modern linguistic theories rely on the notion of constraints. However, only few applications try to implement the parsing process directly with constraint programming: in most cases, constraints are interpreted in a passive sense, the parsing process itself being no diierent to that of classical deriva-tional approaches. We show in this paper that the problem comes from the representati...

In call centers it is crucial to staff the right number of agents so that the targeted service levels are met. These staffing problems typically lead to constraint satisfaction problems that are hard to solve. During the last decade, a beautiful many-server asymptotic theory has been developed to solve such problems for large call centers, and optimal staffing rules are known to obey the square...

Computational experiments are reported involving the concept of foreknowledge, an agent’s direct, unmediated and accurate, but possibly incomplete, awareness of its future including states and events involving the agent itself. Foreknowledge is used here as a conceptual tool with which to explore certain issues around time and rationality. We first explain how foreknowledge in this sense may be...

We propose an OT-theoretic typology of vowel harmony systems based on a comparative study of front/back harmony. Harmony processes are governed by a general constraint that imposes feature agreement on neighboring segments. Disharmonic (“neutral”) segments arise when this constraint is dominated by markedness constraints and/or by faithfulness constraints that govern segment inventories. These ...

Despite successful application of constraint programming (CP) to solving many real-life problems there is still an indispensable group or researchers considering (wrongly) CP as a simple evaluation technique only. Even if sophisticated search algorithms play an important role in solving constraint-based models, the real power engine behind CP is called constraint propagation (domain filtering, ...

This paper discusses a case of syntax/semantics interaction of a characteristically optimality-theoretic kind. Finnish partitive constructions exhibit a case alternation that is partly semantically, partly syntactically driven. The crucial semantic condition that plays a role in case selection is quantitative determinacy, which replaces the de niteness condition familiar from the Partitive Cons...

We perform a detailed theoretical and empirical comparison of the dual and hidden variable encodings of non-binary constraint satisfaction problems. We identify a simple relationship between the two encodings by showing how we can translate between the two by composing or decomposing relations. This translation suggests that we will tend to achieve more pruning in the dual than in the hidden va...

A new approach is presented for determining the rigid regions in proteins and the flexible joints between them. The short-range forces in proteins are modeled as constraints and we use a recently developed formalism from graph theory to analyze flexibility in the bond network. Forces included in the analysis are the covalent bond-stretching and bond-bending forces, salt bridges, and hydrogen bo...

Constraint Handling Rules (CHR) are our proposal to allow more exibility and application-oriented customization of constraint systems. CHR are a declarative language extension especially designed for writing user-deened constraints. CHR are essentially a committed-choice language consisting of multi-headed guarded rules that rewrite constraints into simpler ones until they are solved. In this b...