Sherali-Adams relaxations for valued CSPs

Johan Thapper (1) , Stanislav Živný (2)

1 LIGM - Laboratoire d'Informatique Gaspard-Monge
2 University of Oxford

We consider Sherali-Adams linear programming relaxations for solving valued constraint satisfaction problems to optimality. The utility of linear programming relaxations in this context have previously been demonstrated using the lowest possible level of this hierarchy under the name of the basic linear programming relaxation (BLP). It has been shown that valued constraint languages containing only finite-valued weighted relations are tractable if, and only if, the integrality gap of the BLP is 1. In this paper, we demonstrate that almost all of the known tractable languages with arbitrary weighted relations have an integrality gap 1 for the Sherali-Adams relaxation with parameters (2, 3). The result is closely connected to the notion of bounded relational width for the ordinary constraint satisfaction problem and its recent characterisation.

Domaines: Complexité [cs.CC]; Algorithme et structure de données [cs.DS]; Mathématique discrète [cs.DM]; Logique en informatique [cs.LO]

Johan Thapper, Stanislav Živný. Sherali-Adams relaxations for valued CSPs. 42nd International Colloquium on Automata, Languages, and Programming (ICALP-2015), 2015, Kyoto, Japan. ⟨hal-01762339⟩