We say goodbye this month to a profoundly inspiring mathematician and economist, David Gale. His influential paper with Lloyd Shapely entitled College Admissions and the Stability of Marriage in 1962 introduced the much-loved stable marriage problem to the literature. The problem asks how a matchmaker in a village can arrange marriages such that no couple wants to divorce their assigned partner and run off together. Such a set of marriages is called "stable", and the set of stable marriages turns out to have a beautiful and endlessly amusing mathematical structure, uncovering such universal truths as "the proposing side of the market ends up with the best partner." (I.e., be proactive in your personal life?) Beyond giving professors and students endless hours of fun and amazing lectures, the stable marriage problem has also had significant impact in many practical settings by providing policy-makers a powerful tool with which to design centralized markets like public school choice and the National Residency Matching Program (NRMP). While the stable marriage work is perhaps Gale's most well-known contribution, he has also contributed significantly to many other fields of math and economics, about which I am much less qualified to comment. He also developed a sort of online museum of mathematical concepts MathSite, which includes some really neat interactive exhibits and is accessible to people of all ages and skill levels.
David Gale was 85, and is survived by his partner, Sandra Gilbert, three daughters, and two grandsons.