He tackled problems related to dissipative nonlinear ordinary differential equations but did not take the usual approach of using linear theory to tackle nonlinear differential equations.
He tackled mga problema na kaugnay sa dissipative nonlinear karaniwang kaugalian equation ngunit hindi umabot ang mga karaniwang pamamaraan ng paggamit sa guhit teorya sa pamingwit nonlinear kaugalian equation.