Stanisław Ruziewicz (29 August 1889 – 12 July 1941) was a Polish

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change. History On ...

and one of the founders of the

Lwów School of Mathematics The Lwów school of mathematics ( pl, lwowska szkoła matematyczna) was a group of Polish mathematicians who worked in the interwar period in Lwów, Poland (since 1945 Lviv, Ukraine). The mathematicians often met at the famous Scottish Café t ...

. He was a former student of

Wacław Sierpiński Wacław Franciszek Sierpiński (; 14 March 1882 – 21 October 1969) was a Polish mathematician. He was known for contributions to set theory (research on the axiom of choice and the continuum hypothesis), number theory, theory of functions, and to ...

, earning his doctorate in 1913 from the

University of Lwów The University of Lviv ( uk, Львівський університет, Lvivskyi universytet; pl, Uniwersytet Lwowski; german: Universität Lemberg, briefly known as the ''Theresianum'' in the early 19th century), presently the Ivan Franko Na ...

; his thesis concerned

continuous function In mathematics, a continuous function is a function such that a continuous variation (that is a change without jump) of the argument induces a continuous variation of the value of the function. This means that there are no abrupt changes in value ...

s that are not

differentiable In mathematics, a differentiable function of one real variable is a function whose derivative exists at each point in its domain. In other words, the graph of a differentiable function has a non-vertical tangent line at each interior point in its ...

. He became a professor at the same university (then named Jan Kazimierz University) and

rector Rector (Latin for the member of a vessel's crew who steers) may refer to: Style or title *Rector (ecclesiastical), a cleric who functions as an administrative leader in some Christian denominations *Rector (academia), a senior official in an edu ...

of the

Academy of Foreign Trade in Lwów Academy of Foreign Trade in Lwów ( pl, Akademia Handlu Zagranicznego we Lwowie, ''AHZ'') was one of four colleges in the city of Lwów in the interbellum period, when it belonged to the Second Polish Republic (now Lviv, Ukraine). It existed be ...

. During the

Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

, Ruziewicz's home city of

Lwów Lviv ( uk, Львів) is the largest city in western Ukraine, and the seventh-largest in Ukraine, with a population of . It serves as the administrative centre of Lviv Oblast and Lviv Raion, and is one of the main cultural centres of Ukraine ...

was annexed by the

Ukrainian Soviet Socialist Republic The Ukrainian Soviet Socialist Republic ( uk, Украї́нська Радя́нська Соціалісти́чна Респу́бліка, ; russian: Украи́нская Сове́тская Социалисти́ческая Респ ...

, but then taken over by the

General Government The General Government (german: Generalgouvernement, pl, Generalne Gubernatorstwo, uk, Генеральна губернія), also referred to as the General Governorate for the Occupied Polish Region (german: Generalgouvernement für die be ...

German-occupied Poland German-occupied Poland during World War II consisted of two major parts with different types of administration. The Polish areas annexed by Nazi Germany following the invasion of Poland at the beginning of World War II—nearly a quarter of the ...

in July 1941; Ruziewicz was arrested and murdered by the

Gestapo The (), abbreviated Gestapo (; ), was the official secret police of Nazi Germany and in German-occupied Europe. The force was created by Hermann Göring in 1933 by combining the various political police agencies of Prussia into one organi ...

on 12 July 1941 in Lwów, during the

Massacre of Lwów professors In July 1941, 25 Polish academics from the city of Lwów (now Lviv, Ukraine) along with the 25 of their family members were killed by Nazi German occupation forces. By targeting prominent citizens and intellectuals for elimination, the Nazis hop ...

. The

Ruziewicz problem In mathematics, the Ruziewicz problem (sometimes Banach–Ruziewicz problem) in measure theory asks whether the usual Lebesgue measure on the ''n''-sphere is characterised, up to proportionality, by its properties of being finitely additive, invari ...

, asking whether the

Lebesgue measure In measure theory, a branch of mathematics, the Lebesgue measure, named after French mathematician Henri Lebesgue, is the standard way of assigning a measure to subsets of ''n''-dimensional Euclidean space. For ''n'' = 1, 2, or 3, it coincides wit ...

on the sphere may be characterized by certain of its properties, is named after him..

References

1889 births 1941 deaths Lwów School of Mathematics Victims of the Massacre of Lwów professors People from the Kingdom of Galicia and Lodomeria People from Kolomyia Polish people executed by Nazi Germany {{Poland-mathematician-stub