Kolmogorov's theorem is any of several different results by Andrey Kolmogorov:
In statistics Kolmogorov–Smirnov test In real analysis Kolmogorov–Arnold representation theorem In probability theory Hahn–Kolmogorov theorem Kolmogorov extension theorem Kolmogorov continuity theorem Kolmogorov's three-series theorem Kolmogorov's zero–one law Chapman–Kolmogorov equations Kolmogorov inequalities Kolmogorov's inequality Kolmogorov's inequality for positive submartingales In functional analysis Landau–Kolmogorov inequality Fréchet–Kolmogorov theorem