was a Japanese mathematician. A world-renowned expert in functional equations, he is best known for discovering "Haruki's theorem" and "Haruki's Lemma" in plane geometry. Some of his published work, such as: "On a Characteristic Property of Confocal Conic Sections" is available (open source) on Project Euclid. Haruki earned his MSc and PhD from Osaka University and taught there. He was a professor at the University of Waterloo in Canada from 1966 till his retirement in 1986. He was a founding member of the university's computer science department (1967). See also List of University of Waterloo people References News release, Department of Computer Science, University of Waterloo. External links Haruki's theorem on MathWorld Hiroshi Haruki's Lemma (Interactive Mathematics Miscellany and Puzzles) Hiroshi Haruki's Theorem (Interactive Mathematics Miscellany and Puzzles) Year of birth missing 1997 deaths Euclidean geometry Canadian mathematicians 20th-century Japanese mathematicians University of Waterloo faculty Osaka University alumni