---
tag: S5TNA2RWYY
kind: concept
name: Internal
sources:
  - wikipedia: en:325802@r1373839425
    locator: Glossary of graph theory, section I
    note: adopted
    mention: wikipedia://en/325802#1P2J
    sections: [Summary]
inventory: [KMFEQCCKBX]
---

## Summary

A vertex of a path or tree is internal if it is not a leaf; that is, if its degree is greater than one. Two paths are internally disjoint (some people call it *independent*) if they do not have any vertex in common, except the first and last ones.