Zobrazeno 1 - 10
of 160
pro vyhledávání: '"Gyssens, Marc"'
We show that the matrix query language $\mathsf{MATLANG}$ corresponds to a natural fragment of the positive relational algebra on $K$-relations. The fragment is defined by introducing a composition operator and restricting $K$-relation arities to two
Externí odkaz:
http://arxiv.org/abs/1904.03934
Autor:
Hellings, Jelle, Gyssens, Marc, Wu, Yuqing, Van Gucht, Dirk, Bussche, Jan Van den, Vansummeren, Stijn, Fletcher, George H. L.
Motivated by the continuing interest in the tree data model, we study the expressive power of downward navigational query languages on trees and chains. Basic navigational queries are built from the identity relation and edge relations using composit
Externí odkaz:
http://arxiv.org/abs/1803.01390
Publikováno v:
In Journal of Logical and Algebraic Methods in Programming April 2022 126
Given a document D in the form of an unordered node-labeled tree, we study the expressiveness on D of various basic fragments of XPath, the core navigational language on XML documents. Working from the perspective of these languages as fragments of T
Externí odkaz:
http://arxiv.org/abs/1502.03258
Autor:
Hellings, Jelle, Gyssens, Marc, Wu, Yuqing, Van Gucht, Dirk, Van den Bussche, Jan, Vansummeren, Stijn, Fletcher, George H.L.
Publikováno v:
In Information Systems March 2020 89
A lattice-theoretic framework is introduced that permits the study of the conditional independence (CI) implication problem relative to the class of discrete probability measures. Semi-lattices are associated with CI statements and a finite, sound an
Externí odkaz:
http://arxiv.org/abs/1408.2030
Autor:
Fletcher, George H. L., Gyssens, Marc, Leinders, Dirk, Surinx, Dimitri, Bussche, Jan Van den, Van Gucht, Dirk, Vansummeren, Stijn, Wu, Yuqing
Publikováno v:
Information Sciences (2015), pp. 390-406
Motivated by both established and new applications, we study navigational query languages for graphs (binary relations). The simplest language has only the two operators union and composition, together with the identity relation. We make more powerfu
Externí odkaz:
http://arxiv.org/abs/1401.8201
Autor:
Fletcher, George H. L., Gyssens, Marc, Leinders, Dirk, Bussche, Jan Van den, Van Gucht, Dirk, Vansummeren, Stijn
Motivated by applications in databases, this paper considers various fragments of the calculus of binary relations. The fragments are obtained by leaving out, or keeping in, some of the standard operators, along with some derived operators such as se
Externí odkaz:
http://arxiv.org/abs/1210.2688
Publikováno v:
Proceedings of the 24th Conference on Uncertainty in Artificial Intelligence, 2008, pages 435-443
A lattice-theoretic framework is introduced that permits the study of the conditional independence (CI) implication problem relative to the class of discrete probability measures. Semi-lattices are associated with CI statements and a finite, sound an
Externí odkaz:
http://arxiv.org/abs/0810.5717
Typechecking consists of statically verifying whether the output of an XML transformation always conforms to an output type for documents satisfying a given input type. In this general setting, both the input and output schema as well as the transfor
Externí odkaz:
http://arxiv.org/abs/cs/0606094