287 PETRYANOV-SOKOLOV 



Bibliography: 



Uber das Cauchysche Problem fur Systeme von partiellen 



Differentialgleichungen. Mathematical Collection. New 



Series, 1937,^(44), #5. 



On the topology of real plane algebraic curves in Annales of 



Mathematics. Princeton-New York: 1938, 39, #1, 197-209. 



Sur I'analyticite des solutions des systems d' equations 



differentielles. Mathematical Collection. New Series, 1939, 



^(47), #1. 



On the diffusion of waves and the lacunas for hyperbolic 



equations. Mathematical Collection, New Series, 1945, 17 



(59), #3. 



and E. M. Landis . On the number of limiting cycles of the 



equation -r- = ^ / {* where P and Q are polynomials of the 

 dx Q(x, y) 



second power. Mathematical Collection, 1955, _37, #2, 209- 



250. 



and E. M. Landis. On the number of limiting cycles of 



equation 'T~ - r>) (> where P and Q are polynomials. Dok- 



lady Akad. Nauk S.S.S.R., 1957, 113, #4. 

 Biography: 



S. D. Sobolev . On the 50th Anniversary of Ivan Georgievich 



Petrovskii. Izvest. Akad. Nauk S.S.S.R., Ser. Mat., 1951, 



15, #3. 



A. N. Kolmogorov . Ivan Georgievich Petrovskii. On the 



50th Anniversary since the date of birth. Uspekhi Mat. 



Nauk, 1951, #3 (43) (contains bibliography of the works of 



Petrovskii). 

 Office: Moscow University 



Moscow, USSR 

 Residence: Leninskii Prospekt, 13 



Moscow, USSR 

 Telephone: V2 14 47 



PETRYANOV-SOKOLOV, IGOR' VASIL'EVICH (Physical 

 Chemist) 

 I. V. Petryanov-Sokolov was born June 18, 1907. After 

 graduating from Moscow University in 1930, he worked at the 

 Karpov Physico-Chemical Institute. In 1947 he became pro- 

 fessor at the Moscow Chemico-Technological Institute. He has 

 been a Corresponding Member of the U.S.S.R. Academy of 

 Sciences since 1953. In 1941 he received a Stalin Prize. 



