just defined VRT and VP1 fespae
difined you matrix A, B and C with varf, va, vb,vc;
varf va([u1,u2],[v1,v2]) = … ;
varf vb(p,[v1,v2]) = …;
varf vc(p,q) = …;
matrix A = va(VRT,VRT);
matrix B = vb(VP1,VRT);// warning test function corresponding to row index.
matrix C = vb(VP1,VP1);
matrix K = [[A,B],[B’,C]];