Mixed schemes for quad-curl equations

Abstract

In this paper, mixed schemes are presented for two variants of quad-curl equations. Specifically, stable equivalent mixed formulations for the model problems are presented, which can be discretized by finite elements of low regularity and of low degree. The regularities of the mixed formulations and thus equivalently the primal formulations are established, and some finite elements examples are given which can exploit the regularity of the solutions to an optimal extent.