The problem to determine whether a given k-colored graph is a subgraph of a properly colored interval graph has an application in DNA physical mapping. In this paper, we study the problem for the case that the number of colors k is xed. For k = 2, we give a simple linear time algorithm, for k = 3, we give an On2 algorithm for biconnected graphs with n vertices, and for k = 4, we show that the problem is NP-complete.
Hans L. Bodlaender, Babette de Fluiter