**Wacław Franciszek Sierpiński** (IPA: vaʦwaf fraɲʨiʂɛk ɕɛrpʲiɲskʲi). He was born on 14 as March as 1882 , Warsaw and died on 21 October as as 1969 in Warsaw) was a Polish mathematician. Notable are his contributions to set theory , the theory of numbers , topology and function theory . In set theory he made important contributions to the axiom of choice and the continuum hypothesis. He studied the theory of the curve that describes a closed path that contains all the interior points of a square. He published more than 700 works and 50 books.

Three known fractals are named: the Sierpinski triangle , the Sierpinski carpet and curve Sierpinski . Sierpinski’s numbers in number theory have also been named after him.

## Summary

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- 1 Education
- 2 Contributions to mathematics
- 3 Honors received
- 4 Publications
- 5 External links

## Education

Sierpiński entered the Department of Mathematics and Physics at the University of Warsaw in 1899 and graduated four years later.

In 1903 , while he was still in university, the Department of Mathematics and Physics offered a prize for the best essay by a student on the contribution of Georgi Voronói to *number theory* . The gold medal was awarded to Sierpiński for what was his first great mathematical contribution. Unwilling to have the work published in Russian, he retained it until 1907 , when it was published in Samuel Dickstein’s mathematical journal “Works of Mathematics and Physics.”

After graduation in 1904 , Sierpiński worked as a teacher of mathematics and physics at a Warsaw school. However, when the school closed due to a strike, Sierpiński decided to go to Krakow to get his doctorate. At the Jagiellonian University in Krakow, he attended Stanisław Zaremba lectures on mathematics. He also studied astronomy and philosophy. He received his doctorate and was appointed to the University of Lwów in 1908.

## Contributions to mathematics

Sierpiński square, a fractal.

In 1907 Sierpiński became interested in set theory when he came across a theorem that the points on the plane could be determined with a single coordinate.

He wrote to Tadeusz Banachiewicz (who was then at Göttingen), asking how such a result was possible. He received a laconic one-word reply: “Cantor.” Sierpiński began studying set theory and in 1909 gave his first lecture entirely devoted to this area of mathematics.

Sierpiński maintained an extraordinary rate of production of research papers and books. Between 1908 and 1914 , when teaching at the University of Lwów , he published three books as well as numerous research papers.

The titles of these books are The Theory of Irrational Numbers ( 1910 ), Structure of Set Theory ( 1912 ), and The Theory of Numbers (1912).

When World War I began in 1914 , Sierpiński and his family were in Russia. Aiming to avoid the very frequent persecution of Polish foreigners in Russia, Sierpiński worked in Moscow with Nikolái Luzin until the war ended. Together, they began the study of analytical sets. In 1916 , Sierpiński gave the first example of a normal number.

When the war ended in 1918 , Sierpiński returned to Lwów. However, shortly after his appointment, the University of Warsaw offered him a position, which he accepted. He remained in Warsaw for the rest of his life.

During the Polish-Soviet War ( 1919 – 1921 ), Sierpiński contributed to deciphering Russian crypto codes at the Polish crypto agency.

In 1920 , Sierpiński, together with Zygmunt Janiszewski and his former student Stefan Mazurkiewicz , founded an influential mathematical journal, “Fundamenta Mathematica”, specializing in works on set theory. During this period, Sierpiński worked primarily on set theory, but also on topology of sets of points and functions of a real variable. In set theory, he made contributions to the axiom of choice and the continuum hypothesis. He also worked on what is currently known as the Sierpiński curve. It also continued to collaborate with Luzin in the investigation of analytical and projective sets. In your study of the functions of a real variable you can find results on functional series, differentiability of functions and the Baire classification.

Sierpiński was very involved in the development of mathematics in Poland. He was elected to the Polska Akademia Umiejętności in 1921 and that same year he was appointed dean of the faculty of the University of Warsaw. In 1928 he was appointed vice-president of the administrative council of the Warsaw Scientific Society, and that same year he was elected president of the administrative council of the Polish Mathematical Society.

Sierpiński was the author of 724 works and 50 books. He retired in 1960 as a professor at the University of Warsaw, but continued to work until 1967 to teach a seminar on number theory at the Polish Academy of Sciences. He also continued his editorial work in Acta Arithmetica, Rendiconti del Circolo Matematico di Palermo, Composito Matematica and Zentralblatt für Mathematik.

## Honors received

Amsterdam Lwów 1929 , San Marcos de Lima 1930 , 1931 , Tarta 1931 , Sofía 1939 , Praga 1947 , Wroclaw 1947 , Lucknow 1949 and Moscow honorary titles 1967 .

For the high participation and development of mathematics in Poland, Sierpinski was honored with the election of the Polish Academy of Learning in 1921 and that same year he was dean of the faculty of the University of Warsaw.

In 1928, he became vice-president of the Warsaw Scientific Society, and that same year he was elected president of the Polish Mathematical Society.

He was elected member of the Geographical Society of Lima ( 1931 ), the Royal Scientific Society of Liège ( 1934 ), the Bulgarian Academy of Sciences ( 1936 ), the National Academy of Lima ( 1939 ), the Royal Society of Sciences of Naples (1939) ), the Accademia dei Lincei de Roma ( 1947 ), the German Academy of Sciences ( 1950 ), the United States of the National Academy of Sciences (1959), the Academy of Paris (1960), the Royal Dutch Academy ( 1961 ) , the Brussels Academy of Sciences (1961), the London Mathematical Society ( 1964 ), the Romanian Academy ( 1965 ) and thePontifical Academy of Sciences ( 1967 ).

In 1949 Sierpinski was awarded the First Grade Polish Scientific Prize.