“…All the aforementioned works, whichever the problem they may be analyzing (elasticity, heat diffusion, free flow, Darcy flow, etc), treat separately the primal and dual mixed formulations (see [8], [9], [10]). The present paper is focused on using simultaneously both fundamental versions for the treatment of multiscale problems in Darcy flow (see Problem (1)), it is therefore a primal-dual mixed formulation; in a way this article is the numerical implementation of the formulation introduced in [11] (see also [12], [13] for related formulations). The stability aspects become particularly critical when dealing with multiscale problems, as the presence of physical coefficients with different orders of magnitude adds up to the built-in complexity of the mixed variational formulations (coefficient a(·) in Problem (1)).…”