Tadyei Ivanovich Zyelyenyak is one of the pupils of academician S.L.Sobolev. He is doctor in physics and mathematics (1970), Head of the laboratory of Institute of mathematics named after S.L.Sobolev, the expert in the field of the differential equations. T.I.Zyelyenyak is the author and the co-author of 98 scientific works, including 4 monographs. More than 35 years he was the professor in the Novosibirsk state university, where he headed the department of applied mathematics, he is full professor. Among his pupils are 10 doctors and more than 30 candidates of science. T.I. Zyelyenyak is the winner of the premium of the President of Russian Federation in the field of education for 2000.

Professor T.I. Zyelyenyak is the first researcher of the USSR, who actively studied the mathematical problems into the theory and practice of catalytic processes. He developed the qualitative theory of the equations with partial derivatives. In the field of the nonlinear equations of parabolic type that describe catalytic systems, he has proved existence theorems, the theorem of stabilization of the limited decisions to stationary ones, and he has obtained effective stability criteria. He worked in the Institute of mathematics of SB AS USSR from the first days upon its organization, he has created the great scientific school. A part of his pupils worked in the Department of kinetics and modeling of the Institute of catalysis of SB AS USSR. As a result of cooperation of these two Institutes, mathematical methods were introduced into the science on catalysis.