Algebra Paolo Aluffi 《Algebra》 · 第 110 页 · Chapter II，Section 9.3「Transitive actions and the category G-Set」，Definition 9.6 An action of a group $G$ on a nonempty set $A$ is transitive if for all $a,b\in A$ there exists $g\in G$ such that $b=ga$. 查看原书页面
