Lyapunov stability of compact sets in locally compact metric spaces

Abstract: This paper provides a systematic exposition of Lyapunov stability for compact sets in locally compact metric spaces. We explore foundational concepts, including neighborhoods of compact sets, invariant sets, and the properties of dynamical systems, and establish key results on the relationships between attraction, invariance, and stability. The work explores Lyapunov stability within the context of dynamical systems, highlighting equivalent formulations and related criteria. Central to the exposition is a proof of the fundamental theorem linking Lyapunov functions to the asymptotic stability of compact sets. This expository piece consolidates results from several classical texts to provide a unified and accessible framework for understanding stability in metric spaces.