Ivan Vladislavovich Sleshinsky or Jan Śleszyński () (23 July 1854 – 9 March 1931) was a Polish-Russian mathematician. He was born in Lysianka, Russian Empire to Polish parents. Life Śleszyński's main work was on continued fractions, least squares and axiomatic proof theory based on mathematical logic. He and Alfred Pringsheim, working separately, proved what is now called the Śleszyński–Pringsheim theorem. His most important publications include: "Teoria dowodu" ("The theory of proof") in two volumes (1925, 1929), and "Teoria wyznaczników" ("The theory of determinants") (1926). He is buried at Rakowicki Cemetery. See also History of philosophy in Poland List of Poles References External links 1854 births 1931 deaths 19th-century Polish mathematicians 20th-century Russian mathematicians Burials at Rakowicki Cemetery Polish mathematicians Polish logicians Proof theorists