Since meeting in graduate school, Doug and I have been friends and collaborators for around 45 years. Over that period of time, we have written many papers and travelled together many times. In this talk, I will discuss some of the problems that were left unresolved in several of our papers. Some old photos may show up too.

Bio: Jeff Dinitz is Professor Emeritus and former Williams Professor of Mathematics in the Department of Mathematics and Statistics at the University of Vermont. He has served as chair for two departments, editor-in-chief of the Journal of Combinatorial Designs, is co-editor-in-chief of the CRC Handbook of Combinatorial Designs, and once "played" with the XFL. Jeff is interested in computational and algebraic methods for determining the structure and existence of combinatorial configurations, such as designs and graphs, as well as related algorithms and applications. You can find Jeff on the ski slopes, bike trails, or waves of Lake Champlain when he is not doing mathematics.