SOCG

This volume collects the research papers and the short descriptions of the video/multimedia presentations of the 21st Annual Symposium on Computational Geometry (SoCG'05), held June 8-10, 2005, in Pisa, Italy. In addition, there are two invited talks by Giuseppe di Battista (on clustered planarity) and by Eli Goodman (on double-permutation sequences and geometric transversals). The symposium is sponsored by SIGACT and SIGGRAPH, two Special Interest Groups of the Association for Computing Machinery (ACM).In total, 141 papers were submitted to the conference (2 papers were subsequently withdrawn). The Program Committee undertook an extensive review and selection process, with a distributed effort that included expert input not only from the Program Committee, but also from numerous external reviewers. Almost 600 reviews were written for the selection process, totalling more than a Megabyte of text. We wish to acknowledge the substantial help that we received from external reviewers: Their names are listed on pages viii-ix. The Program Committee met electronically from January 25 to February 14, producing 482 discussion items with more than 190 Kilobytes of text. The 41 papers of this volume were eventually selected for presentation at the symposium.For handling the on-line submission process, we adapted the free version of the CyberChair software of Richard van de Stadt. The Program Committee review, discussion and decision phase was done using the UMIACS Echelon (copyright) software, developed by Yang Wang at the University of Maryland.The papers generally represent preliminary results of ongoing research. It is expected that most papers will eventually appear in a more polished and complete form in refereed journals.In addition to the paper submissions, there were 13 submissions with a total playtime of 64 minutes in response to the Call for Videos and Multimedia, of which 11 were accepted. One of the accepted videos accompanies an accepted paper submission, an option that was encouraged in this year's call for papers. It was not only possible to submit video, but also more interactive forms of multimedia, such as applets and PowerPoint animations. This year, two submissions were Java applets and one submission was a Macromedia Flash presentation; all three were accepted. These proceedings contain a short description of each of the accepted contributions. The web proceedings showcase the video and multimedia submissions; see http://videos.compgeom.org/