“…As a consequence, Pyragas control has many different successful applications, e.g., in atomic force microscopes, 32 un-manned helicopters, 21 complex robots, 29 semiconductor lasers, 24,25 and the enzymatic peroxidase-oxidase reaction, 19 among others. The success of Pyragas control has been verified for a large number of specific theoretical models as well, including spiral breakup in cardiac tissues, 23 flow alignment in sheared liquid crystals, 30 near Hopf bifurcation 3 and unstable foci, 12,33 synchrony in networks of coupled Stuart-Landau oscillators, 26,27 delay equations, 6,7 in quantum systems, 2,10 the Duffing oscillator, 5 and Turing patterns. 18 General conditions on the success or failure of Pyragas control are hard to obtain because the time delay adds infinitely many dimensions to the complexity of the dynamical system.…”