Patrick Dehornoy

Patrick Dehornoy (September 11, 1952 – September 4, 2019) was a French mathematician.
He worked at the University of Caen. He found one of the first applications of large cardinals to algebra. This was called the Dehornoy order, on the braid group. He was one of the main workers to the development of Garside methods in group theory.
His works helped solved the word problem of general Artin–Tits groups.
Dehornoy died on September 4, 2019 in Caen, France at the age of 66.