Felix Klein
German mathematician, author of the Erlangen Program (1849-1925)
Felix Christian Klein (April 25, 1849, Düsseldorf, Prussian Empire – June 22, 1925, Göttingen, Germany) was a German mathematician. He became known for his work in group theory, function theory, non-Euclidean geometry, and on the connections between geometry and group theory. His 1872 Erlangen Program, which ate geometries by their underlying symmetry groups, was a hugely influential synthesis of much of the mathematics of the day.
![](http://up.wiki.x.io/wikipedia/commons/thumb/e/e2/Felix_Klein.jpeg/220px-Felix_Klein.jpeg)
The Klein bottle is named after him.