      <li>Locally <b>stable</b> in the sense of Lyapunov (i.s.L.).  A fixed
        point, $x^*$ is locally stable i.s.L. if for every (small) $\epsilon >
        0$, $\exists~\delta > 0$ such that if $\| x(0) - x^* \| <
        \delta$ then $\forall t$ $\| x(t) - x^*\| < \epsilon$.  In words, this
        means that for any ball of size $\epsilon$ around the fixed point, I
        can create a ball of size $\delta$ which guarantees that if the system
        is started inside the $\delta$ ball then it will