 Chebyshev's students included Aleksandr Lyapunov, who founded the modern stability theory, and Andrey Markov who invented the Markov chains.In the 20th century Soviet mathematicians, such as Andrey Kolmogorov, Israel Gelfand, and Sergey Sobolev, made major contributions to various areas of mathematics.Nine Soviet/Russian mathematicians were awarded with the Fields Medal, a most prestigious award in mathematics.