He was known for his research in automata theory and formal languages, much of which he published in collaboration with Hermann Maurer and Arto Salomaa, and also for his work in computational geometry.
[2] He earned his PhD from Leeds in 1968 under the supervision of Mike Wells.
He died on 4 October 2010 in Sunnyside Long-Term Care, Kitchener, where he moved after his retirement.
[1] The Journal of Universal Computer Science published a special issue in honor of his 70th birthday.
[2][5] The University of Waterloo continues to offer an annual graduate scholarship in his memory.