Logarithmic Convexity and impulse Approximate Controllability for Degenerate Parabolic Equations with Robin Boundary Conditions
Hind El Baggari, Ilham Ouelddris
TL;DR
This work addresses approximate controllability for a one-dimensional degenerate parabolic equation with Robin boundary conditions at the degeneracy point, subject to an impulsive control in a small region at time \\tau. The authors develop a Carleman commutator-based logarithmic convexity framework to establish a single-time observability inequality for the adjoint system, which they then use to derive null approximate impulse controllability for all final times \\ T, with an explicit cost bound \\mathcal{P}(T,\\epsilon) \\le \\frac{1}{\\epsilon^{\\beta}} e^{\\mathcal{C}(1+1/(T-\\tau))}. The analysis hinges on weighted Sobolev spaces \\ H^1_\\alpha, \\ H^2_\\alpha and a carefully chosen weight \\phi to control boundary terms under Robin conditions. The results provide a constructive, quantitative path to controllability in degenerate parabolic systems with convective boundary effects and impulsive actuation, while highlighting open questions for interior-only control regions.
Abstract
In this work, we investigate the approximate controllability of a class of one-dimensional degenerate parabolic equations with Robin boundary conditions. The degeneracy occurs at one endpoint of the spatial domain, and we apply an impulsive control in a small region at a fixed moment. Our main result establishes an observability inequality for the adjoint system, from which we deduce approximate controllability at final time . The proof relies on a logarithmic convexity argument, developed through a Carleman commutator approach.
