Because of their relation to S4, interior algebras are sometimes called S4 algebras or Lewis algebras, after the logician C. I. Lewis, who first proposed the modal logics S4 and S5.
因为它们与 S4 的关系，内部代数有时叫做 S4 代数或 Lewis 代数，得名于逻辑学家 C. I. Lewis，他首先提议了模态逻辑 S4 和 S5。