Definition:Extension of Rooted Tree

Definition
Let $\left({T, r_T}\right)$ and $\left({S, r_S}\right)$ be rooted trees.

Then $\left({S, r_S}\right)$ is an extension of $T$ iff:


 * $T$ is a subtree of $S$;
 * $r_S = r_T$.

That is, iff $T$ is a rooted subtree of $S$.

Also see

 * Definition:Extension of Branch of Rooted Tree