In this paper, we consider the following degenerate/singular parabolic equation
$ \begin{align*} u_t -(x^\alpha u_{x})_x - \frac{\mu}{x^{2-\alpha}} u = 0, \qquad x\in (0,1), \ t \in (0,T), \end{align*} $
where $ 0\leq \alpha <1 $ and $ \mu\leq (1-\alpha)^2/4 $ are two real parameters. We prove the boundary null controllability by means of a $ H^1(0,T) $ control acting either at $ x = 1 $ or at the point of degeneracy and singularity $ x = 0 $. Besides we give sharp estimates of the cost of controllability in both cases in terms of the parameters $ \alpha $ and $ \mu $. The proofs are based on the classical moment method by Fattorini and Russell and on recent results on biorthogonal sequences.
Citation: |
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