Before revision:  The Koopman representation of the nonlinear system is then used to synthesize LQRfeedback .
After revision:  The Koopman representation of the nonlinear system has marginally better performance than competing nonlinear modeling methods, such as SINDy and NARX. In addition, as a linear model, the Koopman approach lends itself readily to efficient control design tools, such as LQR, whereas the other modeling approaches require nonlinear control methods .