Translation of Nagumo's Foundational Work on Barrier Functions: On the Location of Integral Curves of Ordinary Differential Equations

Abstract: In 1942, Prof. Mitio Nagumo published his seminal paper on the location of integral curves of ordinary differential equations. Nagumo's paper provides the foundation of the set invariance of ordinary differential equations and barrier functions, which have recently gained popularity for the control design of safety critical dynamical systems. This translation shall serve the community with an easily accessible version of the original 1942 paper in English. A copy of Nagumo's paper in German is also attached as a reference. That copy was created by the Boeing Company, Germany, in an attempt to improve pdf format readability of the original paper.