This idea also helps when thinking about local/global (I'd argue most of what we do is local optimization of minima, and what challenges us is when the assumpti

This idea also helps when thinking about local/global (I'd argue most of what we do is local optimization of minima, and what challenges us is when the assumptions about locality of the phenomenon are challenged enough that we can't guarantee that stability). And the idea is also applicable to trajectories rather than singular points: if you change your starting point by an epsilon, would the trajectory be vastly similar or a bit different? or very different? cue in Lyapunov fun and Lipschitz continuity[0] as a metric and, to a lesser extent, conditions for chaotic trajectories to emerge. [0] https://en.wikipedia.org/wiki/Lipschitz_continuity https://en.wikipedia.org/wiki/Lipschitz_continuity