Demange, MarcEkim, Tinaz2006-09-272006-09-272006-09-272006https://infoscience.epfl.ch/handle/20.500.14299/234159Precoloring extension problems are known to be NP-complete in several classes of graphs. Here, we consider precolorings of cographs with not only stable sets but also with cliques. We give polynomial time algorithms to extend such a precoloring in an optimal way according to several objective functions.text::report