  Attempts to resolve the longstanding Fermion mass hierarchy (FMH) problem in
frames of the AdS/CFT correspondence demand the knowledge of bulk fermion
masses. The approach of the "old" conformal bootstrap in AdS context permitted
to calculate bulk masses of scalar fields [1], [2]. In the present paper this
approach is extended to physically more interesting spin 1/2 bulk fields.
Calculation of spinor-scalar vertices is performed in physical AdS space, and
unexpectedly simple expressions for spinor-scalar bubbles (2-point one-loop
self-energy Witten diagrams) are obtained. The "double-trace from UV to IR
flow" subtraction of UV divergences used earlier in calculations of the
UV-finite bulk tadpoles is applied to bubbles. This permitted to write down in
frame of the "old" conformal bootstrap approach the nontrivial spectral
equations for the bulk fermion masses; SU(N) Yukawa model of spinor fields
interacting with conformal invariant scalar field in case of four boundary
dimensions is considered as a specific example.
