From the 1930s Pontryagin had been friendly with the physicist A A Andronov and had regularly discussed with him problems in the theory of oscillations and the theory of automatic control on which Andronov was working.
Mula sa 1930s Pontryagin had been friendly sa pisisista AA Andronov at may regular na tinalakay sa kanya ang mga problema sa teorya ng oscillations at ang teorya ng awtomatik na kontrol sa kung saan Andronov ay nagtatrabaho.