John McKay (mathematician)

John K. S. McKay (18 November 1939 – 19 April 2022)^[1][2] was a British-Canadian mathematician and academic who worked at Concordia University, known for his discovery of monstrous moonshine, his joint construction of some sporadic simple groups, for the McKay conjecture in representation theory, and for the McKay correspondence relating certain finite groups to Lie groups.