Sathamangalam Ranga Iyengar Srinivasa Varadhan,  (born 2 January 1940) is an Indian American mathematician. He is known for his fundamental contributions to probability theory and in particular for creating a unified theory of large deviations.
Born on January 2, 1940, Sathamangalam Ranga Iyengar Srinivasa Varadhan is an Indian-American mathematician renowned for his pivotal advancements in probability theory, particularly for establishing a cohesive framework of large deviation theory.