On the functional graph of $f(X)=c(X^{q+1}+aX^2)$ over quadratic extensions of finite fields

Abstract

Let $\mathbb{F}_q$ be the finite field with $q$ elements and $char(\mathbb{F}_q)$ odd. In this article we will describe completely the dynamics of the map $f(X)=c(X^{q+1}+aX^2)$, for $a=\{\pm1\}$ and $c\in\mathbb{F}_q^*$, over the finite field $\mathbb{F}_{q^2}$, and give some partial results for $a\in\mathbb{F}_q^*\setminus\{\pm1\}$.