Tractability in Constraint Satisfaction Problems: A Survey Clément Carbonnel, Martin Cooper To cite this version: Clément Carbonnel, Martin Cooper. Tractability in Constraint Satisfaction Problems: A Survey. Constraints, Springer Verlag, 2016, 21 (2), pp.115-144. 10.1007/s10601-015-9198-6. hal-01230685 HAL Id: hal-01230685 https://hal.archives-ouvertes.fr/hal-01230685 Submitted on 18 Nov 2015 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Tractability in Constraint Satisfaction Problems: A Survey ? Clement Carbonnel1;3 and Martin C. Cooper2 1 CNRS, LAAS, 7 avenue du colonel Roche, F-31400 Toulouse, France fcarbonnel,
[email protected] 2 IRIT, University of Toulouse III, 31062 Toulouse, France
[email protected] 3 University of Toulouse, INP Toulouse, LAAS, F-31400 Toulouse, France Abstract. Even though the Constraint Satisfaction Problem (CSP) is NP-complete, many tractable classes of CSP instances have been identified. After discussing different forms and uses of tractability, we describe some landmark tractable classes and survey recent theoretical results. Although we concentrate on the classical CSP, we also cover its important extensions to infinite domains and op- timisation, as well as #CSP and QCSP. 1 What is tractability? The idea that an algorithm is efficient if its time complexity is a polynomial function of the size of its input can be traced back to pioneering work of Cobham [45] and Edmonds [81], but the foundations of complexity theory are based on the seminal work of Cook [52] and Karp [119].