% PC28Mb function [Minc0]=subMinc0(u) Minc0=zeros(4,4); Minc0(1,1)=-1; Minc0(2,1)=1; Minc0(2,3)=-1; Minc0(3,2)=1; Minc0(3,4)=-1; Minc0(4,2)=-1;