Mojżesz David Kirszbraun (1903 or 1904–1942) — Polish mathematician, mostly known for his theorem on extensions of Lipschitz maps. This theorem appears in his master's thesis, defended in Warsaw in 1930.
He finished school in 1922. Together with his classmate, Adolf Lindenbaum he goes to Warsaw University. After finishing study, he works as an actuary in an insurance company. He died in a ghetto in 1942.