We prove the finiteness of ergodic measures of maximal entropy for partially hyperbolic diffeomorphisms where the center direction has a dominated decomposition into one dimensional bundle and there is a uniform lower bound for the absolute value of the Lyapunov exponents.
As applications we prove finiteness for a class derived from Anosov partially hyperbolic diffeomorphisms defined on
T4 and that in a class of skew product over partially hyperbolic diffeomorphisms there exists a
C1 open and
Cr dense set of diffeomorphisms with a finite number of ergodic measures of maximal entropy. We also study the upper semicontinuity of the number of measures of maximal entropy with respect to the diffeomorphism.