Stefan Banach was an original member of the Lwów School of Mathematics and founder of modern functional analysis

Today’s Google Doodle celebrates Stefan Banach, one of the 20th century most influential mathematicians.

Banach was an original member of the Lwów School of Mathematics and founder of modern functional analysis.

The Doodle, which marks the day on which he officially became a professor, shows an illustration of his face surrounded by numbers – here is everything you need to know about him.

Who was Stefan Banach?

Banach was born in Krakow, which was then part of the Austro-Hungarian Empire, on 30 March 1892.

He never knew his mother, and his father sent him to be raised by a family in the city.

Banach was interested in maths from a young age. He used to solve problems during breaks and after school with his best friend, Witold Wiłkosz, who also went on to become a famous mathematician.

When the First World War broke out Banach was excused from military service due to his left-handedness and poor vision.

During the war he met Hugo Steinhaus one of the most celebrated mathematicians of the time, in Krakow, and Steinhaus became fascinated with him and his abilities, given that he was largely self-taught.

Steinhaus was an early founder of game and probability theory, but called Banach his “greatest scientific discovery”.

They began working together and in April 1919 officially founded a society together that became the Polish Mathematical Society.

Steinhaus introduced Banach to his future wife, Łucja Braus, and to many influential professors who helped kick-start his career.

With the help of Steinhaus’ academic connections, Banach founded modern functional analysis, an entirely new branch of mathematics. Many concepts are named after him including Banach spaces, Banach algebra and the Banach-Steinhaus theorem.

The group founded the Lwów School of Mathematics, in what is now known as Lviv.

They began publishing their own journal, Studia Mathematica, which was largely devoted to functional analysis.