TY - GEN

T1 - Finding the next solution in constraint-and preference-based knowledge representation formalisms

AU - Brafman, R.

AU - Rossi, F.

AU - Salvagnin, D.

AU - Venable, K. B.

AU - Walsh, T.

PY - 2010/1/1

Y1 - 2010/1/1

N2 - In constraint or preference reasoning, a typical task is to compute a solution, or an optimal solution. However, when one has already a solution, it may be important to produce the next solution following the given one in a linearization of the solution ordering where more preferred solutions are ordered first. In this paper, we study the computational complexity of finding the next solution in some common preference-based representation formalisms. We show that this problem is hard in general CSPs, but it can be easy in tree-shaped CSPs and tree-shaped fuzzy CSPs. However, it is difficult in weighted CSPs, even if we restrict the shape of the constraint graph. We also consider CP-nets, showing that the problem is easy in acyclic CP-nets, as well as in constrained acyclic CP-nets where the (soft) constraints are tree-shaped and topologically compatible with the CP-net.

AB - In constraint or preference reasoning, a typical task is to compute a solution, or an optimal solution. However, when one has already a solution, it may be important to produce the next solution following the given one in a linearization of the solution ordering where more preferred solutions are ordered first. In this paper, we study the computational complexity of finding the next solution in some common preference-based representation formalisms. We show that this problem is hard in general CSPs, but it can be easy in tree-shaped CSPs and tree-shaped fuzzy CSPs. However, it is difficult in weighted CSPs, even if we restrict the shape of the constraint graph. We also consider CP-nets, showing that the problem is easy in acyclic CP-nets, as well as in constrained acyclic CP-nets where the (soft) constraints are tree-shaped and topologically compatible with the CP-net.

UR - http://www.scopus.com/inward/record.url?scp=84860568618&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:84860568618

SN - 9781577354512

T3 - Proceedings of the International Conference on Knowledge Representation and Reasoning

SP - 425

EP - 433

BT - Principles of Knowledge Representation and Reasoning

PB - Institute of Electrical and Electronics Engineers

T2 - 12th International Conference on Principles of Knowledge Representation and Reasoning, KR 2010

Y2 - 9 May 2010 through 13 May 2010

ER -