Analysis of the null controllability of degenerate parabolic systems of Grushin type via the moments method (Q2064563)

In this paper, authors computed the exact value of the minimal null control time for the Grushin equation controlled on a strip based on the moments method. The approach here is involved in a careful spectral analysis of a truncated harmonic oscillator. The main results also extended some known results on biorthogonal families to real exponentials in the absence of a gap condition to get uniform estimates with respect to the asymptotic behavior of the associated counting function.