S.L. Sobolev pre-war works and their importance for the subsequent development of mathematics

Sobolev is a person of era lifting of Russia, revolutions, wars. These give rise to the era of giants (and not just in science). One of these giants was Sobolev. The main pre-war achievement of Sobolev was an introduction to the mathematics of the following concepts: 1. the concept of a generalized solution of partial differential equations and the theory of such decisions; 2. concepts of generalized functions; 3. Sobolev spaces (their definition, embedding theorems, theorems on compactness of the embedding operator, applications in mathematical physics). It is supposed to tell about the origins and further development of these conceptions.