Add higher powers to the basis such that \( f\in V \):
>>> psi = taylor(x, y, 2, 2) >>> u, c = least_squares(f, psi, Omega) >>> print u 2*x**2*y**2 + x**2 + 2*y**2 + 1 >>> print u-f 0
Expected: \( u=f \) when \( f\in V \)