  This paper deals with the hierarchic control of a degenerate parabolic
equation with missing initial condition. We present a Stackelberg strategy
combining the concept of null controllability with low-regret control. We
assume that we can act on the system through a set of hierarchic controls. The
main control called the leader is in charge of the null controllability while
the second control named the follower solves an optimal control problem
involving a missing data. The main novelty of this work is the derivation of a
new Carleman inequality for a degenerate system, which is used in a standard
way to show observability inequality of the adjoint degenerate systems.
