George H. L. Fletcher, Marc Gyssens, Dirk Leinders, Jan Van den Bussche, Dirk Van Gucht, Stijn Vansummeren, Yuqing Wu. The impact of transitive closure on the expressiveness of navigational query languages on unlabeled graphs. Annals of Mathematics and Artificial Intelligence, 73(1-2):167-203, 2015. [doi]
Abstract is missing.