the boundary conditions, and local and global symmetries, can be written where we have assumed that lepton number is only violated on the UV brane. 3 l denotes the SM-like doublet and ˜ l stands for the other SU (2)$_{L}$ doublet within the given bi-doublet, whereas the dots correspond to higher dimensional operators. We have also introduced the LH and RH chirality projections ζ$_{L,R}$ ≡ [(1 ∓ γ $^{5}$) / 2] ζ , recovering the standard 4D notation. Finally, ( ) α , α = e, µ, τ , are the 3 × 3 combinations transforming under A$_{4}$ as 1 , 1 ′′ and 1 ′ , respectively. As usually in these models, we shall assume that A$_{4}$ × Z$_{8}$ is spontaneously broken by the boundary scalar vacuum expectation values (v.e.v.) resulting in the brane localized terms with the Majorana mass matrix 3 This assumption, which corresponds to the strong sector preserving lepton number, can be obtained as an accidental symmetry by introducing, for instance, larger SO (5) representations. 7 〈 φ 〉 = ( v, 0 , 0) , 〈 η 〉 = v$_{η}$, 〈 φ $^{′}$〉 = ( v ′ , v ′ , v ′ ) and 〈 η $^{′}$〉 = v ′ $_{η}$, (10) − L UV = 1 2 ν ′ c 2 $_{R}$θ$_{M}$ ν ′ 2 R + x$_{l}$ ¯ l$_{1}$$_{L}$l$_{3}$$_{R}$ + h . c . + . . . , −L IR = ( R R ′ ) 4    $^{√$_{3}$}$ v ′ Λ ′    l$_{3}$$_{L}$ $_{Ω}$  $^{y}$$^{e}$ b 0 0 0 y µ b 0 0 0 y τ b    l$_{R}$ + [ l$_{3}$, l → ˜ l$_{3}$, ˜ l ] + e ′ 3 $_{$_{L}$Ω}$  $^{y}$$^{e}$ s 0 0 0 y µ s 0 0 0 y τ s    e ′ $_{R}$   + y$_{b}$ v ′ η Λ ′ [ l$_{1}$$_{L}$l$_{2}$$_{R}$ + ˜ l$_{1}$$_{L}$ ˜ l$_{2}$$_{R}$ ] + y$_{s}$ v ′ η Λ ′ ν ′ 1 $_{L}$ν ′ 2 R } + h . c . + . . . , (11) θ$_{M}$ ≡    x$_{η}$v$_{η}$ Λ 0 0 0 x$_{η}$v$_{η}$ Λ x$_{ν}$v Λ 0 x$_{ν}$v Λ x$_{η}$v$_{η}$ Λ    =    ϵ$_{s}$ 0 0 0 ϵ$_{s}$ ϵ$_{t}$ 0 ϵ$_{t}$ ϵ$_{s}$    , (12) − L UV = x$_{η}$ 2Λ ην ′ c 2 $_{R}$ν ′ 2 R + x$_{ν}$ 2Λ φν ′ c 2 $_{R}$ν ′ 2 R + x$_{l}$l$_{1}$$_{L}$l$_{3}$$_{R}$ + h . c . + . . . , −L IR = ( R R ′ ) 4 { y α b Λ ′ [ ( l$_{3}$$_{L}$φ ′ ) α l$_{αR}$ + ( ˜ l$_{3}$$_{L}$φ ′ ) $^{α}$˜ l$_{αR}$ ] + y α s Λ ′ ( e ′ 3 $_{L}$φ ′ ) α e ′ αR + y$_{b}$ Λ ′ η ′ l$_{1}$$_{L}$l$_{2}$$_{R}$ + η ′ ˜ l$_{1}$$_{L}$ ˜ l$_{2}$$_{R}$ ] + y$_{s}$ Λ ′ η ′ ν ′ 1 $_{L}$ν ′ 2 R } + h . c . + . . . , (9)