Wacław Franciszek Sierpiński (1882 – 1969) and the phenomenon of Polish set theory school

This year marks the 140th anniversary of the birth of the Polish mathematician Wacław Sierpiński, founder of the Warsaw School of Set Theory. The main directions of his research are number theory, set theory, measure theory, topology. Some years spent by him in Moscow, in the atmosphere of a young school of function theory, and collaboration with N.N. Luzin, left an imprint on his further research. Upon returning to his homeland, he managed to captivate and rally colleagues on the basis of the study and use of set theory, measure theory and topology. Set theory did not require prior specialization, it united mathematicians of various directions, and its methods made it possible to obtain results at a much lower cost than the methods of special sections of mathematics. Polish journal "Fundamenta Mathematicae" was founded in 1920, was entirely devoted to set theory, had a "Problems" section, and was published in the main European languages, thanks to which a fruitful international scientific dialogue arose. Numerous studies of Sierpinski himself served as the basis for the studies of his students.