Markov, Andrey Andreyevich[mah(r)kof]
Mathematician, born in Ryazan, Russia. He studied at St Petersburg, where he became professor (1893--1905), before going into self-imposed exile in the town of Zaraisk. A student of Pafnuty Chebyshev, he worked on number theory and probability theory. His name is best known for the concept of the Markov chain, a series of events in which the probability of a given event occurring depends only on the immediately previous event. This has since found many applications in physics, biology, and linguistics.