Stefan Banach was born as an illegitimate child on March 30, 1892 in Kraków (then Austria-Hungary). First he grew up with his grandmother, after her illness in a foster family. At school, he stands out with very good math grades, but otherwise he has less good school grades. At a grammar school he met Witold Wilkosz, with whom he would later work.
After graduating from school, Banach decides to study another course instead of mathematics. Because he thinks he couldn't learn anything new in mathematics. So he leaves Kraków and goes to Lemberg (now Lviv in Ukraine) to study engineering there. However, his studies are progressing slowly, which is probably due to the fact that he has to give private tuition in order to be able to support himself financially.
When the First World War began in 1914, Banach abandoned his studies and left Lemberg for his home town of Kraków. Because of poor eyesight, he is not drafted into the military, but instead has to work in road construction. He also earns money as a teacher at local schools. He also attends mathematics lectures - presumably also with the well-known mathematician Stanisław Zaremb.
There is a chance meeting with Hugo Dyonizy Steinhaus. He tells him about a mathematical problem that is currently bothering him. Banach takes care of this and has solved the riddle after a few days. The two write an article for a trade journal that Zaremba publishes. This was followed by numerous other mathematical contributions by Banach. Eventually he received a teaching position at the Technical University in Lemberg.
Although Banach does not have a degree, he can present a groundbreaking work; he develops a new mathematical sub-area of functional analysis, which gives him a doctorate. The mathematician quickly publishes further contributions on temporal abstract spaces. In 1922 he completed his habilitation and was appointed extraordinary professor. As a result, Banach publishes a new specialist journal together with Steinhaus and writes textbooks on mathematics.
In 1932, the mathematics professor published the standard work on functional analysis. Seven years later he becomes President of the Polish Mathematical Society. Then the Second World War begins and Soviet troops occupy Lviv. Banach then continued his work at a university in Moscow. Here he is even appointed one of the deans. Banach died of lung cancer in Lemburg on August 31, 1945.
Google is honoring Stefan Banach with a doodle this Friday. It shows him in a portrait with a friendly and at the same time a little stern facial expression. It is surrounded by many digits.
Quellen: Spektrum, School of Mathematics and Statistics University of St Andrews
