The Arithmetic of Elliptic Curves
《The Arithmetic of Elliptic Curves》 · 第 70 页 · Chapter III，Section 4「The Endomorphism Ring」，Example 4.6
Let $E$ be defined over the finite field $\mathbb F_q$. The $q$th-power map $\phi_q:E\longrightarrow E$, $\phi_q(x,y)=(x^q,y^q)$, is an endomorphism of $E$, called the $q$th-power Frobenius endomorphism.