Gelfand's son Sergei (SUR'-gay) says his father died Monday of natural causes at a hospital in New Brunswick.
The distinguished professor of mathematics at Rutgers University conducted pioneering research and served as a mentor for many mathematicians. He established correspondence schools in Russia and the United States that made topflight instruction available to budding mathematicians.
His work in the specialty known as representation theory aided physicists working in quantum mechanics. His work in integral geometry was important in the development of medical imaging devices.
Gelfand was buried Tuesday during a small family service.