N.Y. Civil Practice Law & Rules § 1013: Intervention by permission

§ 1013. Intervention by permission. Upon timely motion, any person may

be permitted to intervene in any action when a statute of the state

confers a right to intervene in the discretion of the court, or when the

person's claim or defense and the main action have a common question of

law or fact. In exercising its discretion, the court shall consider

whether the intervention will unduly delay the determination of the

action or prejudice the substantial rights of any party.