Preface - COCOON'2011

The 17th International Computing and Combinatorics Conference (COCOON’2011) took place in Dallas, Texas, USA, August 14–16, 2011. COCOON’2011 provided a forum for researchers working in the areas of Theoretical computer science, discrete mathematics, and their Applications. Papers accepted for presentations of the conference have been through a tough review process. Each paper received at least Three review report and accepting rate is less than 40%. Papers in This special issue are selected from those presented in COCOON’2011, which received a review process again in order to meet the standard of TCS and to have substantial difference compared with conference version. Therefore, the journal version may either be more complete or contain more results. Indeed, some selected paper was rejected during the second review process. We thank all authors for submitting their papers to COCOON’2011. We are grateful to all members of the Program Committee and all external referees for their hardworkwith demanding time constraints.We thank conference local helpers and conference sponsors for their assistance and supports, especially, we wish to give special thanks to University of Texas at Dallas and the National Science Foundation of USA.