William Richard Maximilian Hugo Threlfall (25 June 1888, in Dresden – 4 April 1949, in Oberwolfach) was a British-born German mathematician who worked on algebraic topology. He was a coauthor of the standard textbook Lehrbuch der Topologie. In 1933 he signed the Vow of allegiance of the Professors of the German Universities and High-Schools to Adolf Hitler and the National Socialistic State. Source: Wikipedia (en)