“…The non-constant function V represents the spatial inhomogeneity. The case V ≡ 1 corresponds to the standard Allen-Cahn equation [3] 2 u + u (1 − u 2 ) = 0 in Ω, ∂u ∂ν = 0 on ∂Ω, (1.2) for which extensive literature on transition layer solutions is available, see for instance [1,2,4,15,16,17,18,20,21,22,25,26,27,28,29,31], and the references therein.…”