Transitive Group Action

A Group Action : G × X X \cdot:G\times X\to X is transitive if for every x , y : X : 𝑥 𝑦 𝑋 x,y:X , there exists some g : G : 𝑔 𝐺 g:G such that g x = y 𝑔 𝑥 𝑦 g\cdot x=y . Equivalently, a group action is transitive if the Shear Map , π 2 : G × X X × X : subscript 𝜋 2 𝐺 𝑋 𝑋 𝑋 \langle\cdot,\pi_{2}\rangle:G\times X\to X\times X is an Epimorphism.