8 • L a MN and R a MN are the SU (2)$_{L}$ ⊗ SU (2)$_{R}$ gauge field strengths: • ˜ g , ˜ g ′ , g$_{5}$ are three, in general different, gauge couplings. ˜ g and ˜ g ′ are the direct analogous of their deconstructed counterparts. g$_{5}$ is the bulk coupling, it has mass dimension − 1 $_{2}$, and it is the 5D limit of the g$_{i}$ , as can be seen by Eq. (7) • the brane scalar U is a SU (2)-valued field, with its covariant derivative defined by: in exact analogy with Eq. (4). Note that the field U is analogous to the one that describes the standard Higgs sector in the limit of an infinite Higgs mass [61]. It can be conveniently parametrized in terms of three real pseudo-scalar fields π $^{a}$, • the fermionic terms, which we take to be confined on the brane for simplicity, have the usual SM form. It is important to notice that the action (8) does not define the physics of the model uniquely: we still have the freedom of choosing boundary conditions (BCs) for the fields. This BC ambiguity is absent in deconstructed models: the BCs get implicitly specified by the way in which the discretization of the 5 th dimension is realized. This means that the GD-BESS model described by Eq. (1) already has a specific set of “built-in” BCs. These can be understood by looking at the residual gauge symmetry at the ends of the moose. It is apparent that, after the “flipping” depicted in Fig. 2, at the N th and ( N + 1) th sites, corresponding to y = 0 in the continuum limit, we have the full SU (2)$_{L}$ ⊗ SU (2)$_{R}$ gauge invariance. By contrast, at the 0 th and (2 N + 1) th sites, corresponding to y = πR , the gauge symmetry is broken down to SU (2)$_{L}$ ⊗ U (1)$_{Y}$ . To do this, we have to impose Dirichlet BCs on two of the SU (2)$_{R}$ gauge fields at y = πR , while all the other fields, and all the fields at y = 0 are unconstrained. The complete gauge symmetry breaking pattern is thus as follows: we have a SU (2)$_{L}$ ⊗ SU (2)$_{R}$ gauge invariance in the bulk, unbroken on the y = 0 brane and U = exp( iπ $^{a}$τa 2˜ v ); (12) D$_{µ}$U = ∂$_{µ}$U + iW a L µ τ a 2 U − iW 3 $_{R µ}$U τ 3 2 , (11) L ( R ) a MN = ∂$_{M}$W a L ( R ) N − ∂$_{N}$W a L ( R ) M + iϵ $^{abc}$W b L ( R ) $_{M}$W c L ( R ) $_{N}$; (10) the fields W a L ( R ) represent the continuum limit of the A ai