Paul Schupp
Paul Eugene Schupp (March 12, 1937 – January 24, 2022) was an American-born British professor emeritus of mathematics at the University of Illinois at Urbana Champaign.Together with Roger Lyndon he is the coauthor of the book "Combinatorial Group Theory" which provided a comprehensive account of the subject of Combinatorial Group Theory, starting with the work of Dehn in the 1910s and to late 1970s and remains a modern standard for the subject of small cancellation theory.Together with David Muller he proved that a finitely generated group G has context-free word problem if and only if G is virtually free, which is now known as Muller–Schupp theorem.In 2012, he was named an inaugural fellow of the American Mathematical Society.In 2017, the conference "Groups and Computation" was organized at Stevens Institute of Technology celebrating the mathematical contributions of Paul Schupp.