![\[fig:bkm\]The 1st KK gluon mass in units of $1/z_v$ and coupling of the first KK gluon to a fermion zero mode localized at UV brane as a function of brane kinetic term $\kappa r_{IR}$.](g1ffbk.pdf "fig:")
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![\[fig:gffbkcoup\] Coupling of the first KK gluon (with respect to the zero mode gluon coupling) with $\kappa r_{IR} = 0,1,5,10,20$ (descending) to a fermion zero mode as a function of bulk mass parameter $c$. ](g1ffc.pdf)

Holographic Higgs with Expanded Custodial Symmetry
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The models with a custodial $SU(2)$ symmetry or large IR boundary kinetic terms (combined with the choices of the $c$’s motivated above) continue to be challenged by the large top mass, which we saw did not allow $Q_3$ to be pushed quite as far away as was optimal for the lighter fermions. This results in corrections to the $Z$-$b_L$-$\bar{b}_L$ coupling compared to those of light fermions which are slightly too large for the experimental errors, and push in a direction unhelpful for $A^{FB}_b$ [@Choudhury:2001hs].

In [@Agashe:2006at], it was noticed that a subgroup of the custodial symmetry can protect the $Z$-$b_L$-$\bar{b}_L$ coupling, provided the third generation doublet is embedded in a representation for which the $SU(2)_L$ and $SU(2)_R$ representations (and the third 