Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. In mathematics, the Sierpi ski space (or the connected two-point set) is a finite topological space with two points, only one of which is closed. It is the smallest example of a topological space which is neither trivial nor discrete. It is named after Wac aw Sierpi ski. The Sierpi ski space has important relations to the theory of computation and semantics.Wac aw Franciszek Sierpi ski (March 14, 1882, Warsaw October 21, 1969, Warsaw) was a Polish mathematician. He was known for outstanding contributions to set theory (research on the axiom of choice and the continuum hypothesis), number theory, theory of functions and topology. He published over 700 papers and 50 books.Three well-known fractals are named after him (the Sierpinski triangle, the Sierpinski carpet and the Sierpinski curve), as are Sierpinski numbers and the associated Sierpi ski problem.