Global synchronization of fractional-order quaternion-valued neural networks with leakage and discrete delays

In this paper, without transforming the quaternion-valued neural networks into two equivalent complex-valued systems or four equivalent real-valued systems, a novel class of fractional-order quaternion-valued neural networks with leakage and discrete delays is investigated. To this end, two novel inequalities are established with the aid of properties of quaternion and Caputo fractional derivative. By exploiting Lyapunov method, our established inequalities, fractional-order Razumikhin theorem and some analysis techniques, some criteria ensuring the global asymptotical synchronization and the global Mittag-Leffler synchronization of the considered networks are obtained through designing suitable controllers. Finally, two numerical examples are utilized to show the derived theoretical results. (C) 2019 Elsevier B.V. All rights reserved.