I think it is easier to formulate this case for the global case with mu included (so no Theta/Heaviside functions needed) and it may be useful to also give the matrix form along side with the integral weak form, especially for the last equation. --Onno ________________________________ From: firedrake-bounces@imperial.ac.uk <firedrake-bounces@imperial.ac.uk> on behalf of Anna Kalogirou <a.kalogirou@leeds.ac.uk> Sent: Wednesday, July 27, 2016 11:01:18 AM To: firedrake@imperial.ac.uk Subject: [firedrake] Mixed system Dear all, I am trying to solve the system found in the attached pdf as a mixed system. I want to solve the same problem as the one found here<https://bitbucket.org/annakalog/buoy2d/src/14334d3c20b9f10ed7c1246cde9e3cb60b1c75e4/Inequality%20constraint/?at=master>, but with the use of Schur complements and not linear algebra. In a previous discussion about this problem, Lawrence mentioned that the test function for integral(lambda*Theta(x-Lp)dx) needs to be considered as coming from the real space of constant functions. Could you please elaborate on this? Regards, Anna. <https://bitbucket.org/annakalog/buoy2d/src/14334d3c20b9f10ed7c1246cde9e3cb60b1c75e4/Inequality%20constraint/?at=master> -- Dr Anna Kalogirou Research Fellow School of Mathematics University of Leeds http://www1.maths.leeds.ac.uk/~matak/