Cassius Jackson Keyser
| Cassius Jackson Keyser | |
|---|---|
| Born | 15 May 1862 | 
| Died | 8 May 1947 (aged 84) New York City, New York, US | 
| Nationality | American | 
| Alma mater | Columbia University | 
| Known for | Foundation of mathematics | 
| Spouse | Ella Maud Crow | 
| Scientific career | |
| Fields | Mathematics | 
| Institutions | University of Missouri SUNY New Paltz Washington University in St. Louis Columbia University | 
| Thesis | The Plane Geometry of the Point in Point-Space of Four Dimensions (1901) | 
| Doctoral students | Eric Temple Bell, Emil Post | 
Cassius Jackson Keyser (15 May 1862 – 8 May 1947) was an American mathematician of pronounced philosophical inclinations.