“…The problem in weak form consists in finding a vector of pressure fields , and a vector of Lagrange multiplier fields . After a lengthy reasoning, 72 and considering geometrical domains in which the assumptions made in Section 2.1 hold true, it can be shown that the weak problem derived from (5), (6a), and the interface conditions discussed in Section 2.4 is given by In (12a), the bilinear form is given by: …”