To access the full text documents, please follow this link: http://hdl.handle.net/10459.1/46640

On balanced CSPs with high treewidth
Ansótegui Gil, Carlos José; Béjar Torres, Ramón; Fernàndez Camon, César; Mateu Piñol, Carles
Tractable cases of the binary CSP are mainly divided in two classes: constraint language restrictions and constraint graph restrictions. To better understand and identify the hardest binary CSPs, in this work we propose methods to increase their hardness by increasing the balance of both the constraint language and the constraint graph. The balance of a constraint is increased by maximizing the number of domain elements with the same number of occurrences. The balance of the graph is defined using the classical definition from graph the- ory. In this sense we present two graph models; a first graph model that increases the balance of a graph maximizing the number of vertices with the same degree, and a second one that additionally increases the girth of the graph, because a high girth implies a high treewidth, an important parameter for binary CSPs hardness. Our results show that our more balanced graph models and constraints result in harder instances when compared to typical random binary CSP instances, by several orders of magnitude. Also we detect, at least for sparse constraint graphs, a higher treewidth for our graph models.
2007
Intel·ligència artificial
CSP (Llenguatge de programació)
(c) Association for the Advancement of Artificial Intelligence, 2007
article
Association for the Advancement of Artificial Intelligence
         

Full text files in this document

Files Size Format View
011050.pdf 150.5 KB application/pdf View/Open

Full text files in this document

Files Size Format View

Show full item record

Related documents

Other documents of the same author

 

Coordination

 

Supporters