“…This Lipschitz function satisfies T ϵ (0) = 0,| T ϵ ( σ )|≤ ϵ , and By the definitions of μ ( x ) and E 4 , we can write Let θ be a cutoff function as in . Using for all m , n , T ϵ ( u n − u m ) θ as test function in for ( u n ) and ( u m ) and then subtracting the results, by , we obtain As in , in order to estimate the last term in , let …”