Longtime Queen’s faculty member and former Head of the Department of Mathematics and Statistics, Bob Erdahl, passed away in late December 2022 at the age of 84. Bob was an exceptionally committed mathematician and a great champion of mathematics and statistics at Queen’s. As many people know, he was also an avid sailor, spending many years racing Flying Dutchmans. He was also a keen gardener and he welcomed many people to stay at his home over the years and to share in a locally-sourced meal.

Bob was the middle of three children, born in Washington D.C. He attended Woodrow Wilson High School, followed by an undergraduate degree from Bucknell University. As a university student Bob explored interests in engineering and chemistry and was co-captain of the varsity swim team. He entered Princeton University in 1960 as a chemistry PhD student. Large-scale scientific computing had just burst on the scene, and Bob exploited this revolutionary tool to analyze the structure of several complex molecules. Gradually, however, his interests turned from chemistry to mathematics. He graduated from Princeton with a doctorate in Quantum Theory in 1966 and moved to Canada where he joined the Mathematics and Statistics Department at Queen’s University, his lifetime academic home.

During his career at Queen’s Bob was deeply involved in Cold War diplomacy and spearheaded scientific exchanges with the Soviet Union between 1978 and 1991. This program sent researchers between the Steklov Institute for Advanced Mathematics in Moscow and St. Petersburg and Queen’s University, with participation from other Canadian universities as well. Bob made annual trips, acquiring a second language and a Rubel prize in 1991 for a research paper written jointly with Sergei Ryshkov, who was a prominent guest at Bob’s home over the years.

Generally regarded as exceptional for his imaginative leadership and dogged persistence, while at Queen’s Bob was dedicated to the prosperity of the Department of Mathematics and Statistics. He organized international conferences including The Coleman Symposium; established the Coleman Postdoctoral Fellowship Program; co-founded the M.Sc. Engineering & Mathematics degree program; for seven years was Chair of Graduate Studies; and he was instrumental in securing Queen’s with a Fields Institute Full Membership. In 2004 he stepped down from his position as Department Head.

Bob retired into his research and continued to publish. In his final years he could often be seen at the Juniper Café, working on mathematical problems related to the Voronoi Conjecture and engaging other patrons in conversation. His vegetable garden also blossomed during his retirement, transforming into a community project with the help of friends, and yielding several seasons of outstanding pesto dinner parties. Bob’s exceptional commitment to mathematics, to life, and to his friends was matched only by his love for family and devotion to his daughters. Bob will be remembered for his generous sense of friendship which extended into so many different communities.