Controllability issues for parabolic–elliptic systems involving nonlocal couplings

Abstract This work addresses controllability properties for some systems of partial differential equations in which the main feature is the coupling through nonlocal integral terms. In the first part, we study a nonlinear parabolic–elliptic system arising in mathematical biology and, using recently developed techniques, we show how Carleman estimates can be directly used to handle the nonlocal terms, allowing us to implement well-known strategies for controlling coupled systems and nonlinear problems. In the second part, we investigate fine controllability properties of a simplified 1-d linear nonlocal coupled system using spectral analysis techniques. In those cases, we will see that the controllability of the concerned model can fail and it will depend on particular choices and combinations of local and nonlocal couplings.