Theoretical analysis of a multi-objective controllability problem for the linear wave equation on a non-cylindrical domain
Pedro Paulo A. Oliveira, Isaías P. de Jesus, Gilcenio R. de Sousa-Neto
TL;DR
This work studies a multi-objective Stackelberg boundary control problem for the linear wave equation on a moving domain $Q_{T,\alpha}$, with leader and follower controls acting on two boundary portions. A cylindrical transformation via $y=\frac{x}{\alpha(t)}$ yields a forward–adjoint system with a variable-coefficient operator $L$, enabling an optimality framework that first determines follower controls in feedback form and then solves the leader problem through Fenchel–Rockafellar duality, under time thresholds $T>T_1$ (and $T>T_2$ for the second problem). The main results (Theorems $\['M1'\}$ and $\['M2'\}$) establish the existence of leader controls $f$ (and $g$) that achieve approximate controllability to target states while minimizing respective cost functionals, with explicit expressions $f=-\frac{1}{\alpha^2(t)}\varphi_y$ (and similarly for $g$) where $\varphi$ solves an adjoint equation. The analysis relies on a follower–leader decomposition, an optimality system for the followers, a density argument ensuring range-density, and duality to convert the leader problem into a tractable variational problem. The results generalize prior work from linear boundaries to more general moving-boundary functions and point to extensions to other PDEs and multi-objective equilibria such as Stackelberg–Nash and Pareto approaches.
Abstract
In this article, we investigate certain theoretical aspects of the hierarchical controllability problem in one-dimensional wave equations within a moving domain using Stackelberg strategy. The controls are applied along a portion of the boundary and establish an equilibrium strategy among them, considering a leader control and a follower. We consider a linear wave equation.
