The hardness of intervalizing four colored caterpillars Original Research Article

The problem of intervalizing colored graphs (ICG) has received a lot of attention due to their use as a model for DNA physical mapping with ambiguous data. If k is the number of colors, the problem is known to be NP-complete for general graphs for k⩾4 and has polynomial time algorithms for k=2 and 3. In this paper we show that the ICG problem is NP-complete when the graph is a caterpillar tree, colored with k⩾4 colors, strengthen the cases for which the problem remains difficult.