Editing Wacław Sierpiński

{{Short description|Polish mathematician (1882–1969)}}
{{distinguish|Anna Sierpińska}}
{{redirect|Sierpiński|the fractals named after him|Sierpiński Triangle|Sierpiński_carpet|Sierpiński_curve}}
{{Infobox scientist
|name              = Wacław Sierpiński  
|image             = Wacław Sierpiński.jpg
|alt               = 
|caption           = Sierpiński in 1928
|birth_name=Wacław Franciszek Sierpiński
|birth_date        = {{birth date|1882|03|14|df=y}}
|birth_place       = [[Warsaw]], [[Congress Poland]], [[Russian Empire]]
|death_date        = {{death date and age|1969|10|21|1882|03|14|df=y}}
|death_place       = [[Warsaw]], [[Polish People's Republic]]
|nationality       = [[Poland|Polish]]
|fields            = [[Mathematics]]
|workplaces        = 
|alma_mater        = [[University of Warsaw]]
|doctoral_advisor  = [[Stanisław Zaremba (mathematician)|Stanisław Zaremba]]<br>[[Georgy Voronoy]]
|doctoral_students = [[Jerzy Browkin]]<br>[[Edward Marczewski]]<br>[[Stefan Mazurkiewicz]]<br>[[Jerzy Neyman]]<br>[[Stanisław Ruziewicz]]<br>[[Andrzej Schinzel]]
|known_for         = [[Sierpinski triangle]]<br>[[Sierpinski carpet]]<br>[[Sierpinski curve]]<br>[[Sierpinski number]]<br>[[Menger sponge|Sierpiński cube]]<br>[[Sierpiński's constant]]<br>[[Sierpiński set]]<br>[[Topological game#The Sierpi.C5.84ski game|Sierpiński game]]<br>[[Sierpiński space]]
}}

'''Wacław Franciszek Sierpiński''' ({{IPA|pl|ˈvat͡swaf fraɲˈt͡ɕiʂɛk ɕɛrˈpij̃skʲi|lang|Pl-Wacław Sierpiński.ogg|}}; 14 March 1882 – 21 October 1969) was a [[Polish people|Polish]] [[mathematician]].<ref name="Wacław Sierpiński (1882-1969)">{{cite journal
| last1      = Kuratowski
| first1     = Kazimierz
| title      = Wacław Sierpiński (1882-1969)
| url        = https://eudml.org/doc/205105
| journal    = Acta Arithmetica
| year = 1972
| volume     = 21
| issue      = 1
| pages      = 1–5
| doi = 10.4064/aa-21-1-1-5
| access-date = 2022-08-28
| doi-access= free
}}</ref> He was known for contributions to [[set theory]] (research on the [[axiom of choice]] and the [[continuum hypothesis]]), [[number theory]], theory of [[function (mathematics)|function]]s, and [[topology]]. He published over 700 papers and 50 books.

Three well-known [[fractal]]s are named after him (the [[Sierpiński triangle]], the [[Sierpiński carpet]], and the [[Sierpiński curve]]), as are [[Sierpiński number]]s and the associated Sierpiński problem.

==Early life and education==
{{Cipher Bureau}}
Sierpiński was born in 1882 in Warsaw, [[Congress Poland]], to a doctor father Konstanty and mother Ludwika (''née'' Łapińska).<ref>{{Cite web |url=https://www.sejm-wielki.pl/b/psb.29410.1 |language=pl |title=Wacław Franciszek Sierpiński |access-date=23 November 2024}}</ref> His abilities in mathematics were evident from childhood. He enrolled in the Department of Mathematics and Physics at the [[University of Warsaw]] in 1899 and graduated five years later.<ref>{{Cite web |url=https://bialczynski.pl/2015/08/20/wielcy-polacy-waclaw-sierpinski-1882-1969-genialny-matematyk/ |language=pl |title=Wielcy Polacy – Wacław Sierpiński (1882 – 1969) – genialny matematyk, Trójkąt, Wolna Wola, Gra w Chaos i Cud nad Wisłą 1920. |website=bialczynski.pl |date=20 August 2015 |access-date=27 April 2023}}</ref> 

In 1903, while still at the University of Warsaw, the Department of Mathematics and Physics offered a prize for the best essay from a student on [[Georgy Voronoy|Voronoy]]'s contribution to number theory. Sierpiński was awarded a gold medal for his essay, thus laying the foundation for his first major mathematical contribution. Unwilling for his work to be published in [[Russian language|Russian]], he withheld it until 1907, when it was published in [[Samuel Dickstein (mathematician)|Samuel Dickstein]]'s mathematical magazine 'Prace Matematyczno-Fizyczne' (Polish: 'The Works of Mathematics and Physics').

After his graduation in 1904, Sierpiński worked as a school teacher of mathematics and physics in Warsaw. However, when the school closed because of a strike, Sierpiński decided to go to [[Kraków]] to pursue a [[doctorate]]. At the [[Jagiellonian University]] in Kraków, he attended lectures by [[Stanisław Zaremba (mathematician)|Stanisław Zaremba]] on [[mathematics]]. He also studied [[astronomy]] and [[philosophy]]. In 1906, he received his doctorate and in 1908 was appointed to the [[University of Lwów]].<ref>{{Cite book |last=Engelking |first=Ryszard |title=Wacław Sierpiński (1882–1969) His Life and Work in Topology |publisher=Springer |year=1998 |isbn=978-90-481-5023-6 |location=Dordrecht |pages=401}}</ref> In 1910, he became head of the Faculty of Mathematics at the university.<ref name="Paulina Rowińska">{{Cite web |url=https://wyborcza.pl/AkcjeSpecjalne/7,160474,24501452,zaczynali-od-zera-stali-sie-legenda-jak-warszawscy-matematycy.html |language=pl |title=Zaczynali od zera, stali się legendą. Jak warszawscy matematycy podbili świat |website=wyborcza.pl |author=Paulina Rowińska |date=8 March 2019 |access-date=27 April 2023}}</ref>

==Career==
[[File:Sierpinski square.png|thumb|left|Sierpinski square, a [[fractal]]]]

In 1907 Sierpiński first became interested in [[set theory]] when he came across a theorem which stated that points in the plane could be specified with a single coordinate. He wrote to [[Tadeusz Banachiewicz]] (then at [[Georg August University of Göttingen|Göttingen]]), asking how such a result was possible. He received the one-word reply '[[Georg Cantor|Cantor]]'. Sierpiński began to study [[set theory]] and, in 1909, he gave the first ever lecture course devoted entirely to the subject.<ref name="Paulina Rowińska"/>

Sierpiński maintained an output of research papers and books. During the years 1908 to 1914, when he taught at the University of [[Lwów]], he published three books in addition to many research papers. These books were  ''The Theory of Irrational Numbers'' (1910), ''Outline of Set Theory'' (1912), and ''The Theory of Numbers'' (1912).

[[File:Wacław Siepiński grave.JPG|thumb|Grave of Wacław Sierpiński]]

When [[World War I]] began in 1914, Sierpiński and his family were in [[Russia]]. To avoid the persecution that was common for [[Poland|Polish]] foreigners, Sierpiński spent the rest of the war years in [[Moscow]] working with [[Nikolai Luzin]]. Together they began the study of [[analytic set]]s. In 1916, Sierpiński gave the first example of an [[normal number|absolutely normal number]].<ref>{{Cite web |url=https://mathshistory.st-andrews.ac.uk/Biographies/Sierpinski/#:~:text=In%201916%2C%20during%20his%20time%20in%20Moscow%2C%20Sierpi%C5%84ski,I%20ended%20in%201918%2C%20Sierpi%C5%84ski%20returned%20to%20Lemberg. |title=Wacław Sierpiński |website=mathshistory.st-andrews.ac.uk |access-date=27 April 2023}}</ref>

When [[World War I]] ended in 1918, Sierpiński returned to [[Lwow|Lwów]]. However shortly after taking up his appointment again in [[Lviv|Lwów]] he was offered a post at the [[Warsaw University|University of Warsaw]], which he accepted. In 1919 he was promoted to a [[professor]]. He spent the rest of his life in [[Warsaw]].<ref>{{Cite web |url=https://www.polskieradio.pl/39/156/Artykul/1738959,Waclaw-Sierpinski-Badacz-zagadek-nieskonczonosci |language=pl |title=Wacław Sierpiński. Badacz zagadek nieskończoności |website=polskieradio.pl |access-date=27 April 2023}}</ref>

During the [[Polish–Soviet War]] (1919–1921), Sierpiński helped break [[Russian SFSR|Soviet Russia]]n [[cipher]]s for the [[Poland|Polish]] [[General Staff]]'s [[Cipher Bureau (Poland)|cryptologic agency.]]

In 1920, Sierpiński, together with [[Zygmunt Janiszewski]] and his former student [[Stefan Mazurkiewicz]], founded the mathematical journal ''[[Fundamenta Mathematicae]]''.<ref name="Wacław Sierpiński (1882-1969)" /> Sierpiński edited the journal, which specialized in papers on [[set theory]].

During this period, Sierpiński worked predominantly on [[set theory]], but also on [[point set topology]] and [[function (mathematics)|function]]s of a [[Function of a real variable|real variable]]. In [[set theory]] he made contributions on the [[axiom of choice]] and on the [[continuum hypothesis]]. He proved that [[Zermelo–Fraenkel set theory]] together with the [[Generalized continuum hypothesis]] imply the [[Axiom of choice]]. He also worked on what is now known as the [[Sierpiński curve]]. Sierpiński continued to collaborate with Luzin on investigations of analytic and projective sets. His work on [[function (mathematics)|function]]s of a [[Function of a real variable|real variable]] includes results on [[functional series]], [[differentiability]] of functions and [[Baire's classification]].

Sierpiński worked at the [[Institute of Mathematics of the Polish Academy of Sciences|State Institute of Mathematics]], which was incorporated into the [[Polish Academy of Sciences]] in 1952.<ref>{{Cite web |url=https://www.impan.pl/en/insitute/about-us/history |title=History |website=impan.pl |access-date=7 December 2024}}</ref> He retired in 1960 as [[professor]] at the [[Warsaw University|University of Warsaw]], but continued until 1967 to give a seminar on the [[Number theory|Theory of Numbers]] at the [[Polish Academy of Sciences]]. He also continued editorial work as editor-in-chief of ''[[Acta Arithmetica]]'', and as a member of the editorial board of ''[[Rendiconti del Circolo Matematico di Palermo]]'', ''Composito Matematica'', and ''[[Zentralblatt MATH|Zentralblatt für Mathematik]]''.

In 1964 he was one of the signatories of the so-called [[Letter of 34]] to Prime Minister [[Józef Cyrankiewicz]] regarding freedom of culture.<ref>{{Cite web |url=https://dzieje.pl/kultura-i-sztuka/list-34-pierwszy-duzy-protest-wobec-polityki-kulturalnej-wladz-prl |language=pl |title=List 34 - pierwszy duży protest wobec polityki kulturalnej władz PRL |website=dzieje.pl |date=10 March 2019 |access-date=27 April 2023}}</ref>

Sierpiński is interred at the [[Powązki Cemetery]] in [[Warsaw]], [[Poland]].<ref>{{Cite web |url=https://cmentarze.um.warszawa.pl/pomnik.aspx?pom_id=3806 |language=pl |title=Warszawskie Zabytkowe Pomniki Nagrobne |access-date=27 April 2023}}</ref>

==Honors received==
Honorary Degrees: [[Lwów]] (1929), [[St. Marks of Lima]] (1930), [[Tartu]] (1932), [[Amsterdam]] (1932), [[Sofia]] (1939), [[Paris]] (1939), [[Bordeaux]] (1947), [[Prague]] (1948), [[Wrocław]] (1948), [[Lucknow]] (1949), and [[Moscow State University|Moscow]] (1967).

For high involvement with the development of [[mathematics]] in [[Poland]], Sierpiński was honored with election to the [[Polish Academy of Learning]] in 1921 and that same year was made [[dean (education)|dean]] of the [[Faculty (division)|faculty]] at the [[University of Warsaw]]. In 1928, he became vice-[[chairman]] of the [[Warsaw]] Scientific Society, and that same year was elected chairman of the [[Polish Mathematical Society]].

He was elected to the Geographic Society of [[Lima, Peru|Lima]] (1931), Royal Scientific Society of [[Liège]] (1934), [[Bulgarian Academy of Sciences]] (1936), National Academy of [[Lima, Peru|Lima]] (1939), Royal Society of Sciences of [[Naples]] (1939), [[Accademia dei Lincei]] of [[Rome]] (1947), [[German Academy of Natural Scientists Leopoldina|Germany Academy of Sciences]] (1950),<ref name="Wacław Sierpiński (1882-1969)" /> [[American Academy of Arts and Sciences]] (1959), [[French Academy of Sciences|Paris Academy]] (1960), [[Royal Netherlands Academy of Arts and Sciences|Royal Dutch Academy]] (1961),<ref>{{cite web|url=http://www.dwc.knaw.nl/biografie/pmknaw/?pagetype=authorDetail&aId=PE00002984 |title=W. Sierpinski (1882 - 1969) |publisher=Royal Netherlands Academy of Arts and Sciences |access-date=17 July 2015}}</ref> [[The Royal Academies for Science and the Arts of Belgium|Academy of Science of Brussels]] (1961), [[London Mathematical Society]] (1964), [[Romanian Academy]] (1965) and Papal Academy of Sciences (1967).

In 1946, he received the [[Polish Mathematical Society#Stefan Banach Prize|Stefan Banach Prize]] of the Polish Mathematical Society. In 1949, Sierpiński was awarded Poland's Scientific Prize, first degree.

In 2014, a sculpture in the form of a tree inspired by a fractal created by Sierpiński was unveiled at the Wallenberg Square in [[Stockholm]] as part of an exhibition organized by the [[Polish Ministry of Foreign Affairs]] on the 10th anniversary of Poland joining the [[European Union]] and 15th anniversary of Poland joining [[NATO]].<ref>{{Cite web |url=https://dzieje.pl/rozmaitosci/w-sztokholmie-stanelo-matematyczne-drzewo-sierpinskiego |language=pl |title=W Sztokholmie stanęło matematyczne drzewo Sierpińskiego |website=dzieje.pl |date=23 September 2014 |access-date=27 April 2023}}</ref>

== Publications ==
Sierpiński authored 724 papers and 50 books, almost all in Polish. His book ''[[Cardinal and Ordinal Numbers]]'' was originally published in English in 1958. Two books, ''Introduction to General Topology'' (1934) and ''General Topology'' (1952) were translated into English by Canadian mathematician [[Cecilia Krieger]].
Another book, ''[[Pythagorean Triangles]]'' (1954), was translated into English by Indian mathematician Ambikeshwar Sharma, published in 1962, and republished by Dover Books in 2003; it also has a Russian translation.<ref>{{citation
 | last = Hopkins | first = Brian
 | date = January 2019
 | doi = 10.1080/07468342.2019.1547955
 | issue = 1
 | journal = The College Mathematics Journal
 | pages = 68–72
 | title = review of ''Pythagorean Triangles''
 | volume = 50| s2cid = 127720835
 }}</ref> Another work of his published in English is the ''Elementary Theory of Numbers'' (translated by A. Hulanicki in 1964), based on his Polish ''Teoria Liczb'' (1914 and 1959).<ref name="Sierpinski1988">{{cite book|author=W. Sierpinski|title=Elementary Theory of Numbers: Second English Edition (edited by A. Schinzel)|url=https://books.google.com/books?id=ktCZ2MvgN3MC|date=1 February 1988|publisher=Elsevier|isbn=978-0-08-096019-7|page=iv, 5–6}}</ref> Another book, named "250 Problems in Elementary Number Theory" was translated into English (1970) and Russian (1968).

==See also==
* [[Arity|Arity theorem]]
* [[List of Poles#Mathematics|List of Polish mathematicians]]
* [[List of things named after Wacław Sierpiński]]
* [[Menger sponge]]
* [[Seventeen or Bust]]
* [[Sierpinski (crater)|The Sierpiński Moon crater]]
* [[Timeline of Polish science and technology]]

==References==
{{Reflist|35em}}

==External links==
* {{MacTutor Biography|id=Sierpinski}}
* {{MathGenealogy |id=12545}}
* {{cite journal |author=K. Kuratowski |author-link=Kazimierz Kuratowski |title=Wacław Sierpiński (1882-1969) |journal=[[Acta Arithmetica]] |year=1972 |volume=21 |pages=1–5 |doi=10.4064/aa-21-1-1-5 |url=http://matwbn.icm.edu.pl/ksiazki/aa/aa21/aa2111.pdf}}
* {{cite journal |author=A. Schinzel |author-link=Andrzej Schinzel |title=Wacław Sierpinski's papers on the theory of numbers |journal=[[Acta Arithmetica]] |year=1972 |volume=21 |pages=7–13 |doi=10.4064/aa-21-1-7-13 |url=http://matwbn.icm.edu.pl/ksiazki/aa/aa21/aa2112.pdf}}
* {{cite journal |title=Publications of Wacław Sierpiński in the theory of numbers |journal=[[Acta Arithmetica]] |volume=21 |pages=15–23 |url=http://matwbn.icm.edu.pl/ksiazki/aa/aa21/aa2113.pdf}}
* [http://matwbn.icm.edu.pl/ksspis.php?wyd=10 Several of Sierpiński's books], Biblioteka Wirtualna Nauki.
* [http://culture.pl/en/article/sierpinski-fractals-code-breaking-and-a-crater-on-the-moon Sierpiński: Fractals, Code Breaking, and a Crater on the Moon]

{{Fractals}}
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{{DEFAULTSORT:Sierpinski, Waclaw}}
[[Category:1882 births]]
[[Category:1969 deaths]]
[[Category:Warsaw School of Mathematics]]
[[Category:People from Warsaw Governorate]]
[[Category:Number theorists]]
[[Category:Topologists]]
[[Category:Members of the Polish Academy of Learning]]
[[Category:Burials at Powązki Cemetery]]
[[Category:Cipher Bureau (Poland)]]
[[Category:Jagiellonian University alumni]]
[[Category:University of Warsaw alumni]]
[[Category:Academic staff of the University of Warsaw]]
[[Category:Members of the Polish Academy of Sciences]]
[[Category:Members of the Bulgarian Academy of Sciences]]
[[Category:Members of the French Academy of Sciences]]
[[Category:Members of the Royal Netherlands Academy of Arts and Sciences]]
[[Category:Members of the German Academy of Sciences at Berlin]]
[[Category:Recipients of the State Award Badge (Poland)]]
[[Category:Foreign members of the Serbian Academy of Sciences and Arts]]