Bifurcation for a reaction–diffusion system with unilateral obstacles with pointwise and integral conditions

A reaction–diffusion system of activator–inhibitor or substrate-depletion type is considered which is subject to diffusion driven instability. It is shown that obstacles (e.g. a unilateral membrane) for one or both quantities introduce a new bifurcation of spatially non-homogeneous steady states in a parameter domain where the trivial branch is exponentially stable without obstacles. The obstacles are modeled in terms of inclusions. Moreover, simultaneously some of the obstacles can be modeled also using nonlocal integral conditions.