 The simplest sort of one-self theory affirms that God is, because omniscient, omnipotent, and omnibenevolent, the one divine self, and each Person of the Trinity just is that same self. The “Athanasian” creed (on which see section  5.3)  seems to imply that each Person just is God, even while being distinct from the other two Persons. Since the high middle ages trinitarians have used a diagram of this sort to explain the teaching that God is a Trinity.