### Clas-Olaf Selenius

#### 28th September 1922-10th September 1991

The following biographical note on Clas-Olaf Selenius is distilled from an article by C.J.Scriba in Historia Mathematica **19** (1992), 325-327.

On September 10, 1991, the Swedish mathematician Clas-Olaf Selenius passed away in Uppsala at the age of 68. Selenius was born in 1922 in Helsingfors (Helsinki) and received his doctorate from Åbo Academy in 1961. He retired from positions at Åbo Academy and Uppsala University in 1983, but continued to give lectures on the history of mathematics until 1990.

He was interested in various kinds of continued fraction algorithms and their relation to quadratic diophantine equations.

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