Resources: page=16 - Theorem 4.2
[!Theorem 4.2] Let be an equilibrium point for . Let be a continously differentiable function s.t
V(0)=0 ; \text{and} ; V(x)>0, ; \forall , x\neq 0 \ ||x|| \to \infty \implies V(x) \to \infty \ \dot{V}(x)<0, ; \forall , x\neq 0 \end{align}$$
Then is globally asymptotically stable