Andrey Markov

Andrey Andreyevich Markov (14 June [O.S. 2 June] 1856 – 20 July 1922) was a Russian mathematician celebrated for his pioneering work in stochastic processes. He extended foundational results—such as the law of large numbers and the central limit theorem—to sequences of dependent random variables, laying the groundwork for what would become known as Markov chains. To illustrate his methods, he analyzed the distribution of vowels and consonants in Alexander Pushkin's Eugene Onegin, treating letters purely as abstract categories and stripping away any poetic or semantic content. He was also a strong chess player. Markov and his younger brother Vladimir Andreyevich Markov (1871–1897) proved the Markov brothers' inequality. His son, another Andrey Andreyevich Markov (1903–1979), was also a notable mathematician, making contributions to constructive mathematics and recursive function theory.