The expressive power of valued constraints: Hierarchies and collapses.

In this paper we investigate the ways in which a fixed collection of valued constraints can be combined to express other valued constraints. We show that in some cases a large class of valued constraints, of all possible arities, can be expressed by using valued constraints of a fixed finite arity....

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Detalhes bibliográficos
Principais autores: Cohen, D, Jeavons, P, Zivny, S
Formato: Journal article
Idioma:English
Publicado em: 2008
Descrição
Resumo:In this paper we investigate the ways in which a fixed collection of valued constraints can be combined to express other valued constraints. We show that in some cases a large class of valued constraints, of all possible arities, can be expressed by using valued constraints of a fixed finite arity. We also show that some simple classes of valued constraints, including the set of all monotonie valued constraints with finite cost values, cannot be expressed by a subset of any fixed finite arity, and hence form an infinite hierarchy. © Springer-Verlag Berlin Heidelberg 2007.