G. Leitmann's integral transformation for global optimal control

Back in 1967, George Leitmann has published “A Note on Absolute Extrema of Certain Integrals” [1] which later generated much interest in the control systems theory and, in effect, started a new method for global optimal control. In this short paper, some observations, extensions, further developments and perspectives of G. Leitmann's equivalence transformation are discussed to mark his exceptional contribution to control theory and to facilitate further research in this area following the bright idea of George Leitmann's basic Lemma on translational symmetry of certain integrals.