An access structure for generalized transitive closure queries

An access structure that accelerates the processing of generalized transitive closure queries is presented. For an acyclic graph, the access structure consists of source-destination pairs arranged in a topologically sorted order. For a cyclic graph, entries in the structure are approximately topologically sorted. The authors present a breadth-first algorithm for creating such a structure, show how it can be used to process queries, and describe incremental techniques for maintaining it.<
>