Model polynomials of $GF(p)$ as polynomials of $GF(p^n)$
Imagine that we have polynomials $F_1, F_2, \ldots, F_n : \mathbb{F}_p \rightarrow \mathbb{F}_p$.
I need to take \mathbb{F}_p$, n polynomials in n variables $F_1, F_2, \ldots, F_n : \mathbb{F}_p^n \rightarrow \mathbb{F}_p$ variables, which define a map of sets $\mathbb{F}_q \rightarrow \mathbb{F}_q$, $q = p^n$, and try we want to realize find the map as a single univariate polynomial over $\mathbb{F}_q$.
$\mathbb{F}_q$.
This is a follow-up question that is answered already here for the reverse direction.