idempotent-elements的用法和樣例：
例句
- If it is finite and nonempty, then it must contain at least one idempotent.
如果它是有限和非空的，則它必須包含至少一個冪等元。 - This paper is a study on the invertibility of the commutator of scalar-idempotent elements and scalar-involutory elements of a unitary ring.
摘要本文研究在一個有單位元的環中兩個倍冪等元的換位子與兩個倍對合元的換位子的可逆性問題。
