Approximation of Degenerate Hyperbolic Equations with Interior Degeneracy and Applications to Controllability

In this paper, we establish the existence of solutions for a particular class of degenerate hyperbolic equations. Following this, we approximate these degenerate equations by employing a sequence of uniformly hyperbolic equations. Notably, this specific approximation result has remained unexplored in the existing body of literature. Ultimately, we utilize this approximation framework to derive controllability results for the original degenerate hyperbolic equations, marking what could potentially be the inaugural investigation into higher-dimensional degenerate hyperbolic equations.