ALGORITHMS FOR PAGE RETRIEVAL AND HAMILTONIAN PATHS ON FORWARD-CONVEX LINE GRAPHS

The problems of determining whether an undirected graph G is sequentially edge-connected, whether G has a dominating path, and whether there is a Hamiltonian path in the line graph of G are shown to be equivalent. These problems are NP-hard even if G is bipartite. They can be used to model certain page retrieval problems in relational database systems in which a graph called page connectivity graph is used to represent a join operation. Many page connectivity graphs encountered in practice are forward-convex. In this paper we develop an algorithm that solves the above-mentioned problems in O(\E(G)\) time for forward-convex graphs G. (C) 1995 Academic Press, Inc.