Herbert Ryser
Herbert John Ryser (born July 28, 1923 in Milwaukee , † July 12, 1985 in Pasadena ) was an American mathematician who dealt with combinatorics .
Live and act
Ryser studied at the University of Wisconsin (Bachelor 1945, Master 1947), where he received his doctorate in 1948 under Cornelius Joseph Everett (1914–1987) and Cyrus Colton MacDuffee (1895–1961) ("Rationale Vector Spaces"). In 1948/9 he was at the Institute for Advanced Study . In 1949 he was Assistant Professor, 1952 Associate Professor and 1955 Professor at Ohio State University , as well as Marshall Hall . In 1962 he became a professor at Syracuse University and in 1967 at Caltech .
In 1949 he proved with Richard Bruck ("The non existence of certain finite projective planes", Canadian Journal of Mathematics Vol. 1, 1949, pp. 88-92) the Bruck-Ryser-Chowla theorem about possible ordinal numbers n of finite projective planes ( extended to other symmetrical block plans by him and Sarvadaman Chowla in 1950 ). This has remained the only general theorem of the non-existence of certain finite projective planes until today . In 1982 he gave a simpler proof of the theorem ("The existence of symmetric block designs", Journal Combinatorial Theory, vol. 32, p. 103), as did Hanfried Lenz at the same time .
In 1970 he was invited speaker at the International Congress of Mathematicians in Nice (New types of combinatorial designs) and in 1962 in Stockholm ( The width of a (0,1) matrix , with Delbert Ray Fulkerson ).
Fonts
- Combinatorial Mathematics (Carus Mathematical Monographs; Vol. 14). MAA , Providence, RI 1963.
Web links
- Biography at the University of Ohio
- Bruck-Ryser-Chowla theorem at Mathworld
| personal data | |
|---|---|
| SURNAME | Ryser, Herbert |
| ALTERNATIVE NAMES | Ryser, Herbert John (full name) |
| BRIEF DESCRIPTION | American mathematician |
| DATE OF BIRTH | July 28, 1923 |
| PLACE OF BIRTH | Milwaukee |
| DATE OF DEATH | July 12, 1985 |
| Place of death | Pasadena |