Open research-level problems in Geometry. Recreational problems and puzzles have their own categories.
Collected by Jeff Erickson. Mainly in geometry.
Compiled by David Eppstein of the University of California at Irvine.
Open Problems with Steiner Trees, maintained by Joe Ganley.
A project to record open problems of interest to researchers in computational geometry and related fields.
Thanks to DMOZ, which built a great web directory for nearly two decades and freely shared it with the web. About us