Waclaw Sierpinski was a Polish mathematician of the XX century very known in his country but also all around the world in the mathematics history and particularly for his works on set theory.
Waclaw Sierpinski was born the 14th of March 1882 in Warsaw (Poland). This was during the Russian occupation of Poland so it was difficult for the young gifted man to continue his studies. Indeed the Russians wanted to keep illiteracy in Poland as high as possible so they discouraged learning. But he succeeded entering the Department of Mathematics and Physics of the University of Warsaw in 1899. The University has become Russian in 1869 and all the staff was Russian. He was attracted by the work of one of his teachers Voronov who worked on the number theory.
Sierpinski graduated in 1904 and began working as a mathematics and physics teacher in a girls school in Warsaw. After the school closed because of a strike, he went to the Jagiellonian University in Cracow to study for his doctorate. He learnt mathematics but astronomy and philosophy too. He received his doctorate and was appointed to the university of Lvov in 1908.
Sierpinski started working on the set theory in 1907 and in 1909 he gave the first ever lecture course devoted entirely to set theory. From 1908 to 1914 he wrote a lot of research papers and three books on the subject : The theory of irrational numbers (1910), Outline of set theory (1912) and The theory of numbers (1912). He introduced the theory of the Sierpinski triangle in 1916.
When the First World War began, Sierpinski and his family were in Russia and the Polish question was a political weapon between Austria and Russia; he was interned in Viatka. Other mathematicians help him and he was allowed to go to Moscow where he worked for the rest of the war years with Luzin on the analytic sets. In 1916 he was the first to give an example of an absolutely normal number (number whose digits occur with equal frequency in whichever base it is written).
After the War, he went back to Lvov but shortly after he was offered a post at the University of Warsaw that he accepted. In 1919 he was promoted to professor at Warsaw and spent the rest of his life there. In 1920 he founded the important mathematics journal Fundamenta Mathematica specialised in papers on set theory. Sierpinski was also involved in the development of mathematics in Poland and was honoured to the Polish Academy in 1921.
In 1939 his life changed dramatically with the Second World War but he continued to work in the 'Underground Warsaw University' while his official job was a clerk in the council offices. Then he managed to send his papers in Italy. In 1944 the Nazis burned his house destroying his library and personal letters. He lost a lot of colleagues and students in the war.
He retired in 1960 as professor after having written more than 700 papers and 50 books ! But he continued to give seminar on the theory of numbers up to 1967 and to work as editor for several mathematics journals. He received so many honours that it is impossible to mention them all, for example he was awarded honorary degrees from the University of Lvov (1929), Sofia (1939), Prague (1947) and Moscow (1967). One of the moon craters handles his name, like many other well-known scientists.
He died the 21st of October 1969 in Warsaw.
For the anecdote, one of his students wrote of Sierpinski
that "He did not like any corrections to his papers. When someone suggested
a correction he added a line to it : 'Mr X remarked that ...' ".