Dear Cognitive Science Colleagues,
I am very sad to report that Christian Freksa has passed away. Christian was the Chair of Cognitive Systems in the Faculty of Mathematics and Informatics at University of Bremen in Germany (https://www.cosy.informatik.uni-bremen.de/staff/christian-freksa.html). He was also the Director of the Spatial Cognition Research Center in Bremen and Freiburg, and a Fellow of the European Society for AI. He was a leader in research on knowledge representation and cognitive systems in general, and spatial and temporal reasoning in particular.
In 2019, Colleen Seifert, Christian and I co-chaired the 41st Annual Meeting of the Cognitive Science Society in Montreal, Canada (https://cognitivesciencesociety.org/cogsci-2019/). The three of us worked closely together for more than a year, and then spent a lovely, if very busy, week together in Montreal. I learned that Christian was both wise (he had an answer to almost every problem and he almost always was right about it) and gentle (not once did he express the slightest irritation at any of the many problems that arose during the year). Oh, he also enjoyed good food, good wine, and good conversation.
Christian was a vibrant member of the Cognitive Science Society. It is hard to believe that he is no more with us. We will miss him.