31 citations · 34 across the 4 of their papers we have counts for
4 papers
Comparing Downward Fragments of the Relational Calculus with Transitive Closure on Trees
Jelle Hellings, Marc Gyssens, Yuqing Wu +4
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…
Structural characterizations of the navigational expressiveness of relation algebras on a tree
George H. L. Fletcher, Marc Gyssens, Jan Paredaens +2
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 docume…
Relative Expressive Power of Navigational Querying on Graphs
George H. L. Fletcher, Marc Gyssens, Dirk Leinders +5
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…
External memory bisimulation reduction of big graphs
Yongming Luo, George H. L. Fletcher, Jan Hidders +2
In this paper, we present, to our knowledge, the first known I/O efficient solutions for computing the k-bisimulation partition of a massive directed graph, and performing maintena…