Workshop on Geometric Group Theory and Computer Science ======================================================= Venue July 5-9, 1998. Mount Holyoke College, South Hadley, MA. This workshop is one of the 1998 AMS-IMS-SIAM Joint Summer Research Conferences in the Mathematical Sciences. See the October, November or December AMS Notices for more information. Organizing Committee Gilbert Baumslag, Martin Bridson, James Cannon, Robert Gilman (chair), Michael Shapiro Partial List of Speakers and Participants John Cannon, David Epstein, Steven Gersten, Susan Hermiller, Chuck Miller, Sarah Rees, Mark Sapir, Charles Sims, Paul Schupp, John Stallings. Scientific Program Over the last several years the study of groups given by generators and relations has been invigorated by an influx of ideas from geometry, topology and computer science; the resulting collection of techniques and points of view has become known as geometric group theory. The workshop is devoted to computer theoretic aspects of this new field. Automatic Groups and Word Hyperbolic Groups Automatic groups and word hyperbolic groups are perhaps the best known products of geometric group theory. At the beginning of the century Max Dehn solved the word and conjugacy problems for fundamental groups of orientable surfaces by making use of the underlying hyperbolic geometry. Dehn's ideas led to the theory of small cancellation groups and more recently to some striking connections between geometry and finite automata. The geometry of the known compact 3-manifolds is reflected by restrictions on the structure of their fundamental groups, and in many cases the spirit of these restrictions is captured by the fact that multiplication in the fundamental group can be carried out by finite automata. This fact leads to the definition of automatic groups and to previously unsuspected connections with computer science. Word hyperbolic groups are algebraic analogs of groups acting cocompactly on spaces of negative curvature. They are defined by imposing geometric conditions on the Cayley diagram of a group. It is remarkable that these groups are also characterized by concepts from computer science. They are precisely the groups whose word problem can be solved by a length reducing rewriting system confluent at the identity. Further Connections with Computer Science Another line of research, initiated by computer scientists, concerns the structure of a group and the properties of the formal language of all words defining the identity with respect to a fixed set of generators. This program has produced a number of interesting results, among them the characterization of groups with a free subgroup of finite index as those groups whose word problem is a context-free language, and a complexity-theoretic analog of the Higman Embedding Theorem. Geometric group theory has also inspired new approaches to computation with finitely presented groups. It is well known that almost all questions about these groups are recursively unsolvable. The computational challenge is to devise programs which will work often enough to be useful.