Extending partial representations of circle graphs

Abstract

The partial representation extension problem is a recently introduced generalization of the recognition problem. A circle graph is an intersection graph of chords of a circle. We study the partial representation extension problem for circle graphs, where the input consists of a graph G and a partial representation R' giving some pre-drawn chords that represent an induced subgraph of G. The question is whether one can extend R' to a representation R of the entire G, i.e., whether one can draw the remaining chords into a partially pre-drawn representation. Our main result is a polynomial-time algorithm for partial representation extension of circle graphs. To show this, we describe the structure of all representation a circle graph based on split decomposition. This can be of an independent interest. © 2013 Springer International Publishing Switzerland.