| Jan Śleszyński | |
| Birth Date: | 23 July 1854 |
| Birth Place: | Lysianka, Kiev Governorate, Russian Empire (present-day Ukraine) |
| Death Place: | Kraków, Poland |
| Fields: | Mathematics |
| Workplaces: | Odessa University, University of Kraków |
| Alma Mater: | Odessa University, University of Berlin |
| Doctoral Advisor: | Karl Weierstrass |
| Known For: | Śleszyński-Pringsheim theorem |
| Resting Place: | Rakowicki Cemetery |
Ivan Vladislavovich Sleshinsky[1] or Jan Śleszyński[1] [2] [3] (ru|Иван Владиславович Слешинский) (23 July 1854 – 9 March 1931) was a Polish-Russian mathematician. He was born in Lysianka, Russian Empire to Polish parents.
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).[4] He is buried at Rakowicki Cemetery.[5]