Felix Klein, the famous German mathematician, was born on this day in 1849. The Klein bottle was named after him. It is a mathematical example of a non-orientable surface which has no boundaries. Similarly, the Möbius strip is also a non-orientable surface, but with a border.
The mathematician Felix Klein was born in Düsseldorf in 1849. Germany was not unified at the time, and Dusseldorf was a part of the Kingdom of Prussia (Berlin was its capital). It is interesting to note that Felix Klein married Anne Hegel, the granddaughter of the famous German philosopher Georg Wilhelm Friedrich Hegel.
Klein held the position of a professor at the University of Göttingen, one of the most respected universities in the German territories. He was a doctoral adviser of Grace Chisholm Young, the first woman who received a doctorate in any field in that country. Klein died in Göttingen in 1925. He was 76 years old.