Dear all,

I read from the FreeFem document (page 202, release 4.6) that " **The integral mesh and the mesh associated to test functions or unknown functions can be different in the case of**

**varf form**". I am wondering what this means? for example, if we have two overlapped meshes Th and Ths, and

fespace Vh(Th, P1);

Vh u, v;

fespace Vhs(Ths, P1);

Vhs us;

varf a(u, v) = int2d(Th)( u*v) + int2d(Ths)( u*v)

**Would the above integral gives the following discretised form automatically:**

(A + P’ * B * P ) * u = f

where **us = P* u** with P is the interpolation matrix between mesh Th and Ths, A and B are discretised matrices from Th and Ths respectively?

Best,

Yongxing.