Give a brief sketch of the proof of the following theorem:
Theorem: Let \[ E=\{x:\phi '(x)=0\} \] and let \(M\) be the largest invariant set of (2.14) in \(E\). Then every bounded (for \(t\ge 0\)) semiorbit of (2.14) tends to \(M\) as \(t\to \infty \).