Wacław Franciszek Sierpiński was a Polish mathematician. He was known for contributions to set theory, number theory, theory of functions, and topology. He published over 700 papers and 50 books.

Topology is the part of mathematics concerned with the properties of a geometric object that are preserved under continuous deformations, such as stretching, twisting, crumpling, and bending; that is, without closing holes, opening holes, tearing, gluing, or passing through itself.