He is well known for providing a simple proof of the Quillen–Suslin theorem, a result in commutative algebra, first conjectured by Jean-Pierre Serre in 1955, and then proved by Daniel Quillen and Andrei Suslin in 1976.
Leonid Vaseršteĭn later gave a simpler and much shorter proof of the theorem which can be found in Serge Lang's Algebra.
Leonid Brezhnev | Leonid Kuchma | Leonid Kravchuk | Leonid Gaidai | Leonid Serebrennikov | Leonid Kuravlyov | Leonid Krasin | Leonid Dushkin | Leonid Andreyev | Leonid Sobinov | Leonid Popov | Leonid Plyushch | Leonid Pasternak | Leonid Korchmar | Leonid Yatsenko | Leonid Yakubovich | Leonid Vysheslavsky | Leonid Volodarskiy | Leonid Vaseršteĭn | Leonid Utyosov | Leonid Tălmaci | Leonid Sokov | Leonid Skirko | Leonid Reiman | Leonid Pastur | Leonid Parfyonov | Leonid Minin | Leonid Mikhailovich Shkadov | Leonid Markelov | Leonid Mandelstam |