5.6 Overtaking and Racing Conduct — Sporting Regulations, Article 27

A driver may use any part of the track (within the defined track limits) during the race. Key conduct rules include: A driver is allowed to change direction once to defend a position. A second change of direction to prevent an overtaking manoeuvre constitutes a violation of Article 27.7 ("erratic...

Source: Article 27.7, Article 27.5, Article 27.1

Send this to your friend — argument over.