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 -