153 KELDYSH 



during January 27- February 3, 1960, he served as chairman of 

 the Section on General and Applied Mechanics. Since 1956 he 

 has been a member of the editorial boards of the journals 

 Matematicheskii Sbornik, Novaya Seriya, and Prikladnaya 

 Matematika i Mekhanika. 



Among the honors and awards that have been conferred upon 

 Keldysh are the Order of Labor Red Banner (in 1943, 1945 and 

 1953) and the Order of Lenin (in 1945, 1954 and 1960). He re- 

 ceived a Stalin Prize in 1941 for scientific works in predicting 

 the breakdown of airplanes. In 1960 he was made a member of 

 the Presidium of the Committee for Awarding Lenin Prizes in 

 the Field of Science and Engineering of the Council of Ministers 

 U.S.S.R. 



Keldysh' s interests in mechanics and mathematics are theo- 

 ry of oscillations, aerodynamics, theory of waves on the sur- 

 face of a heavy liquid, impact against water, investigation of an 

 approximate integration of differential equations, potential 

 theory, conformal representation mapping, theory of eigen- 

 functions and eigenvalues of parameters for non self -conjugate 

 differential equations. In hydromechanics, he worked on the 

 theory of non-stabilized motion of a wing. He proved, for gas, 

 the theorem of Zhukovskii. He presented a theory on the solva- 

 bility of the Dirichlet problem in its dependence on boundary 

 conditions. He solved the basic problems of the stability of 

 solutions of the Dirichlet problem. Keldysh developed a theory 

 of approximation of functions of a complex variable by a series 

 of polynomials. Of considerable importance is the work of 

 Keldysh on the theory, calculation and working out of methods 

 for avoiding various types of vibration in an airplane. Since 

 1953 his papers have discussed such topics as thermal exci- 

 tation of sounds, speed of approximation of functions by poly- 

 nomials on arbitrary continua, point character of the spectrum 

 of a certain class of matrices in an analytical space and series 

 of rational fractions. He has been, directing work on the theory 

 of rocket propulsion and on the development of a ballistic theory 

 of space flight. During September 1957, at a meeting celebrat- 

 ing the 100th anniversary of the birth of K. E. Tsiolkovskii, 

 Keldysh spoke on the use of artificial earth satellites in scien- 

 tific research. 



In June 1961, Keldysh received the Hammer and Sickle Gold 

 Medal, and in March 1962, he was elected a delegate from 

 R.S. F.S.R. to the Supreme Soviet. 



