Henry Crapo

Henry Howland Crapo (; August 12, 1932 – September 3, 2019) was an American-Canadian mathematician who worked in algebraic combinatorics. Over the course of his career, he held positions at several universities and research institutes in Canada and France. He is noted for his work in matroid theory and lattice theory. Education and career Crapo was born in Detroit, Michigan, in 1932. He received his Ph.D. in 1964 under the supervision of Gian-Carlo Rota and Kenneth Hoffman. He held academic positions at the University of Waterloo, Université de Montréal, INRIA Rocquencourt, and École des Hautes Études en Sciences Sociales. During his time in Waterloo, Crapo became a Canadian citizen. Crapo is known for his early work in matroid theory, and for related work in lattice theory. He introduced the beta invariant of a matroid, and published the first paper on the Tutte polynomial (though Tutte had already defined an equivalent polynomial in his thesis). Together with Gian-Carlo Rota, Crapo wrote the first book on matroid theory. He is also known for Crapo's Complementation Theorem in poset Möbius Inversion. Crapo wrote 65 mathematical publications during his career. Upon his retirement, Crapo moved to the south of France. He continued some mathematical activity, and hosted several small conferences at his house there. He died on September 3, 2019.