“…If l = 0 or if g has mean value zero with respect to x N , u 0 coincides with the trace on Σ of the limit solution u in Ω + , while, if l ∈]0, +∞[ and g does not have mean value zero with respect to x N , it coincides with the trace of u on Σ only in Ω × ω. In the complementary set, it solves a system depending on l, which is an algebraic equation (see the third equation in (19)) coupled with a diffusion equation with respect to the y variable, involving, as boundary condition on ∂ ω, the trace of u on Σ (see the first two equations in (19)). Also, as for the dependance of the limit problem with respect to a, it may be surprising to notice that the limit problem does not depend on the restriction of a to Ω − × ω × R N .…”