Sudoku Lovers Take Note

Alerted by a friend of Prof. Mendelsohn's passing and significance in the under-pinnings of this particular puzzle fad, I humbly pass this on to you, who like me, may find Sudoku's logical reasoning relaxing. May Nathan Mendelsohn find himself a place where the perpetual Light of peace and grace shines upon him.

NATHAN MENDELSOHN, SCHOLAR 1917-2006 Absent-minded polymath who taught mathematics at the University of Manitoba for 57 years made his name in combinatorics, a dazzling bit of science that no Sudoku puzzle can be without

TORONTO -- Nathan Mendelsohn may well have been the absent-minded professor from central casting. He would go to work by car and return home by bus. His wife would send him shopping and he would come back with the wrong items ("I'll cook what he brings," she once said with a shrug). And there was the time he took his family to the movies and agreed to stand in the rain to buy the tickets while his wife and two sons took shelter indoors. Prof. Mendelsohn decided he didn't want to see the movie after all, so he drove home.

Then there was the brilliant mathematician who saw beauty in the abstract. The Order of Canada member who made his own furniture, jewellery and wine, and delighted in performing hypnosis and magic tricks. The one who never wrote anything down because he didn't have to. With his sly sense of humour, he would appreciate the designation of polymath.

Prof. Mendelsohn taught mathematics at the University of Manitoba for 57 years, ending his career in 2005 as distinguished professor emeritus. He headed the math department for about 20 years, authored 140 research papers -- about double the average professor's career output -- and was a leading light in a branch of pure mathematics called combinatorics, which deals with the abstract relationships of objects to each other. One application is the math that underlies the popular Sudoku puzzles.

His and others' theories bore practical applications in such areas as scheduling, cryptography and software testing, often decades after they were promulgated. Helen, his wife of 62 years, had another name for her husband's work: "dreamy mathematics"