$
norm((u_0)_j-hat(u)_j (t=0))_(L^2 TT^d) &<= norm(u_j - hat(u)_j)_(L^2 delta Omega) \
&<= sqrt(2 max {2h_Omega,d+1} / rho_Omega) norm(u_j - hat(u)_j)_(H^1 (Omega)) \
&<= sqrt(2 max {2h_Omega,d+1} / rho_Omega) C_(1,k,d+1,u_1) lambda_1 (N) N^(-k+1)
$