“…The variational formulation of problem (43) is exactly (8) written for this new space endowed with the corresponding scalar product (6). In this new geometrical setting, the corresponding compactness results (see, for instance, [24] and [32]) imply that there exist 1 ∈ 1 0 (Ω),̂1 ∈ 2 (Ω, 1 per ( 1 )), 2 ∈ 1 0 (Ω), 2 ∈ 2 (Ω, 1 per ( 2 )), such that Γ (̂1) = 0, Γ ( 2 ) = 0 and, up to a subsequence, for → 0, we have: 1 ( 1 ) → 1 strongly in 2 (Ω, 1 ( 1 )), 1 (∇ 1 ) ⇀ ∇ 1 + ∇̂1 weakly in 2 (Ω × 1 ), 2 ( 2 ) → 2 strongly in 2 (Ω, 1 ( 2 )), 2 (∇ 2 ) ⇀ ∇ 2 + ∇ 2 weakly in 2 (Ω × 2 ),…”