“…For numerical schemes, the assumption (2.2) on α G is somehow related to an estimate on the time modulus of continuity of u. In fact, α G is comparable with ∆t ∂ t u, with ∆t the time step (see [2]). However, when no such estimate is available, it is possible to get an estimate of u − v L 1 t,x with only the regularity of α G stated in (1.4) and an estimate of α G only for small t. In order to obtain this result, just average (2.4) with respect to T and then observe that when averaged, the last inequality of (2.28) in the proof below can be replaced by a suitable one since |χ (t)| ≤ Y ε (t)+Y ε (t−T ).…”