On the tractability of coloring semirandom graphs

Julia Böttcher, Dan Vilenchik

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


As part of the efforts to understand the intricacies of the k-colorability problem, different distributions over k-colorable graphs have been analyzed. While the problem is notoriously hard (not even reasonably approximable) in the worst case, the average case (with respect to such distributions) often turns out to be "easy". Semi-random models mediate between these two extremes and are more suitable to imitate "real-life" instances than purely random models. In this work we consider semi-random variants of the planted k-colorability distribution. This continues a line of research pursued by Coja-Oghlan, and by Krivelevich and Vilenchik. Our aim is to study a more general semi-random framework than those suggested so far. On the one hand we show that previous algorithmic techniques extend to our more general semi-random setting; on the other hand we give a hardness result, proving that a closely related semi-random model is intractable. Thus we provide some indication about which properties of the input distribution make the k-colorability problem hard.

Original languageEnglish
Pages (from-to)143-149
Number of pages7
JournalInformation Processing Letters
Issue number3
StatePublished - 16 Oct 2008
Externally publishedYes


  • Average case analysis
  • Graph algorithms
  • Semi-random models
  • k-coloring


Dive into the research topics of 'On the tractability of coloring semirandom graphs'. Together they form a unique fingerprint.

Cite this