“…In analogy with discrete weak gradient, discrete weak divergence is introduced in [31] where the proposed WG mixed finite element method is applicable for general finite element partitions consisting of shape regular polygons in 2D or polyhedra in 3D. At present, WG method has been widely used to solve various partial differential equations, such as Helmholtz equations [19,9,33], linear parabolic equations [17,37,36], Biharmonic problems [18,7], Stokes problems [22], stochastic partial differential equations [40,41], and heat equations [39,38] etc.…”