no code implementations • 22 Dec 2020 • Nofar Carmeli, Nikolaos Tziavelis, Wolfgang Gatterbauer, Benny Kimelfeld, Mirek Riedewald
For each of the two problems, we give a decidable characterization (under conventional complexity assumptions) of the class of tractable lexicographic orders for every CQ without self-joins.
Databases Data Structures and Algorithms
no code implementations • 29 May 2020 • Nofar Carmeli, Xiaolan Wang, Yoshihiko Suhara, Stefanos Angelidis, Yuliang Li, Jinfeng Li, Wang-Chiew Tan
The Web is a major resource of both factual and subjective information.