Today’s Google Doodle is celebrating a Polish mathematician Stefan Banach to mark the day influential academic became a professor.
Banach was one of the 20th century’s most influential mathmeticians, and an original member of the Lwów School of Mathematics and founder of modern functional analysis.
But, who was Stefan Banach?
Here’s everything you need to know...
Who was Stefan Banach?
Banach was born in Kraków, Poland in 1892 - then part of then part of the Austro-Hungarian Empire. He never knew his mother, and his father sent him to be raised by family in the city.
He was deemed unfit for military service during World War 1 due to his poor eyesight, so he instead taught in local schools.
Banach was interested in maths from a young age, and 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.
After publishing mathematical papers he worked on in his spare time, Banach received a job at Lvov Technical University. He was a mostly self-taught mathematician and professor.
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, an early founder of game and probability theory, referred to Banach as 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.
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Banach’s work on modern functional analysis allowed him to become a professor at Lvov Technical University - in present day Lviv, Ukraine - a hundred years ago in 1922.
Throughout the twentieth century, he made major contributions to the theory of topological vector spaces, measure theory, integration, the theory of sets, orthogonal series and functional analysis, which is still studied and used today.
After the takeover of the city by Nazi Germany in World War 2, all universities were closed. Banach, his son and colleagues all employed as lice-feeder for Rudolf Weigl’s typhus research. A louse-feeder was a human sources of blood for lice infected with typhus, which were then used to research possible vaccines against the disease.
Working for Weigl, who saved and sheltered Jews, prevented Banach and his co-workers from being arrested and deported to a concentration camp.
The Red Army freed the city in 1944 and Banach returned to re-establish the university after the war.
However, The Soviet Union was removing Poles from the area, so Banach began planning his return to his home country.
He was soon after diagnosed with lung cancer and was allowed to stay in Lviv. He died in August 1945, aged 53.
The Google Doodle in his honour is seen in the UK, Sweden, Iceland, Germany, Poland, Greece, Bulgaria, Israel, Australia and New Zealand.
What is functional analysis?
Functional analysis is a branch of mathematics, the core of which is formed by the study of vector spaces.
Britannica describes it as a “branch of mathematical analysis dealing with functionals, or functions of functions”.
It adds: “It emerged as a distinct field in the 20th century, when it was realised that diverse mathematical processes, from arithmetic to calculus procedures, exhibit very similar properties.
“A functional, like a function, is a relationship between objects, but the objects may be numbers, vectors, or functions. Groupings of such objects are called spaces.
“Differentiation is an example of a functional because it defines a relationship between a function and another function (its derivative). Integration is also a functional. Functional analysis focuses on classes of functions, such as those that can be differentiated or integrated.”
