Querying Temporal Constraint Networks in PTIMEManolis

We start with the assumption that temporal knowledge usually captured by constraint networks can be represented and queried more effectively by using the scheme of indeenite constraint databases proposed by Koubarakis. Although query evaluation in this scheme is in general a hard computational problem, we demonstrate that there are several interesting cases where query evaluation can be done in PTIME. These tractability results are original and subsume previous results by van Beek, Brusoni, Console and Terenziani.