The Banach–Tarski Paradox
Cut a solid ball into five pieces, move them around, and you have two balls the same size as the first. Nothing was stretched.
192423 min read
Lwów school of mathematics
Stefan Banach
1892 – 1945
The founder of modern functional analysis and the central figure of the Lwów school, which did much of its work in the Scottish Café over a notebook of open problems. Banach spaces, the Hahn–Banach theorem and the Banach fixed point theorem all carry his name. He survived the German occupation feeding lice at Weigl's typhus institute and died of lung cancer in 1945.