  From recent groundbreaking experiments, it is now known that the
Pontecorvo-Maki-Nakagawa-Sakata mixing differs significantly from the
tribimaximal model in which theta_13=0 and theta_23=pi/4. Flavor symmetry can
require that the departures from these two equations are linearly related. T'
and A_4, which successfully accommodated the pre-T2K
Pontecorvo-Maki-Nakagawa-Sakata matrix, predict that 38.07 deg.< theta_23
<39.52 deg. at 95% C.L.. The best fit values, combining the model predictions
with T2K, MINOS, Double Chooz, Daya Bay, and RENO data, are theta_23=38.7 deg.
and theta_13=8.9 deg..
