  This paper concerns with the hierarchical control of the semilinear parabolic
equations with interior degeneracy. By a Stackelberg-Nash strategy, we consider
the linear and semilinear system with one leader and two followers. First, for
any given leader, we analyze a Nash equilibrium corresponding to a bi-objective
optimal control problem. The existence and uniqueness of the Nash equilibrium
is proved, and its characterization is given. Then, we find a leader satisfying
the null controllability problem. The key is to establish a new Carleman
estimate for a coupled degenerate parabolic system with interior degeneracy.
