“…The first step is to obtain a priori estimates for the problem Lε(φ) = h in Ωε, Bj φ = 0, |j| ≤ m − 1 on ∂Ωε, Ωε χiZij φ = 0 for all j = 0, ..., 2m, i = 1, ..., k which involves more orthogonality conditions than those in (4.1). Notice that in the case m = 1, independently from the nonlinearity, a key step in order to prove such result is the fact that the operator Lε satisfies maximum principle in Ωε outside large balls, see ( [23], Lemma 3.1) and [27] for the exponential-type nonlinearity or the surveys [49] and references therein for other nonlinearity issue such as the Brezis-Nirenberg Problem or the Coron's Problem. For our Lε this is not more true and we need a different approach.…”