Three Seals  三法印（諸行無常，諸法無我，寂靜涅槃）  Also known as Three Universal Truths.   1.All phenomena are impermanent.   2.All Dharma are not-self.   3.The eternity is Nirvāṇa.   It is called the seal because it is to certify whether it is the Buddha's teaching or not. 【參照: Four Seals】