If this formal requirement is not met, the arbitration agreement is rendered null and void pursuant to article 357 of the Civil Code, under which the agreement is a legal act which does not comply with the formal requirements stipulated by the law.
根据《民法典》第357条，未满足这一形式要求的仲裁协议即为无效，根据该条，协议为法律行为，不必遵守法律规定的形式要求。