2025/07/21 by Ervedoza, Sylvain, Tendani-Soler, Adrien
#Analysis of PDEs (math.AP) #FOS: Mathematics
paper · doi:10.48550/arxiv.2507.15407
In this article, we provide a description of the reachable space for the heat equation with various lower order terms, set in the euclidean ball of ℝd centered at 0 and of radius one and controlled from the whole external boundary. Namely, we consider the case of linear heat equations with lower order terms of order 0 and 1, and the case of a semilinear heat equations. In the linear case, we prove that any function which can be extended as an holomorphic function in a set of the form Ωα= \ z∈ℂd | |\Re(z)| + α|\Im(z)| < 1\ for some α∈ (0,1) and which admits a continuous extension up to Ωα belongs to the reachable space. In the semilinear case, we prove a similar result for sufficiently small data. Our proofs are based on well-posedness results for the heat equation in a suitable space of holomorphic functions over Ωα for α> 1.