was a Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

ese mathematician

Mathematician

A mathematician is a person whose primary area of study is the field of mathematics. Mathematicians are concerned with quantity, structure, space, and change....

. A world-renowned expert in functional equation

Functional equation

In mathematics, a functional equation is any equation that specifies a function in implicit form.Often, the equation relates the value of a function at some point with its values at other points. For instance, properties of functions can be determined by considering the types of functional...

s, he is best known for discovering "Haruki's theorem" and "Haruki's Lemma" in plane geometry

Plane geometry

In mathematics, plane geometry may refer to:*Euclidean plane geometry, the geometry of plane figures,*geometry of a plane,or sometimes:*geometry of a projective plane, most commonly the real projective plane but possibly the complex projective plane, Fano plane or others;*geometry of the hyperbolic...

.

Haruki earned his MSc and PhD from Osaka University

Osaka University

, or , is a major national university located in Osaka, Japan. It is the sixth oldest university in Japan as the Osaka Prefectural Medical College, and formerly one of the Imperial Universities of Japan...

 and taught there. He was a professor at the University of Waterloo

University of Waterloo

The University of Waterloo is a comprehensive public university in the city of Waterloo, Ontario, Canada. The school was founded in 1957 by Drs. Gerry Hagey and Ira G. Needles, and has since grown to an institution of more than 30,000 students, faculty, and staff...

 in Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

from 1966 till his retirement in 1986. He was a founding member of the university's computer science department (1967).

External links

• Haruki's theorem on MathWorld
• Haruki's Theorem of Overlapping circles at Dynamic Geometry Sketches Also with link to article with a proof.
• Hiroshi Haruki's Lemma (Interactive Mathematics Miscellany and Puzzles)
• Hiroshi Haruki's Theorem (Interactive Mathematics Miscellany and Puzzles)