Diameter of Some Monomial Digraphs

TL;DR

This paper investigates the diameter of monomial digraphs defined over finite fields, providing new bounds and properties for these graphs based on the exponents m and n.

Contribution

It introduces a detailed analysis of the diameter of monomial digraphs over finite fields, extending previous work to include new bounds and structural insights.

Findings

Derived bounds for the diameter of monomial digraphs

Identified conditions affecting the diameter based on m and n

Provided explicit examples illustrating the diameter behavior

Abstract

Let $p$ be a prime, $e$ a positive integer, $q = p^e$, and let $\mathbb{F}_q$ denote the finite field of $q$ elements. Let $f_i : \mathbb{F}_q^2\to\mathbb{F}_q$ be arbitrary functions, where $1\le i\le l$, $i$ and $l$ are integers. The digraph $D = D(q;\bf{f})$, where ${\bf f}=(f_1,\dotso,f_l) : \mathbb{F}_q^2\to\mathbb{F}_q^l$, is defined as follows. The vertex set of $D$ is $\mathbb{F}_q^{l+1}$. There is an arc from a vertex ${\bf x} = (x_1,\dotso,x_{l+1})$ to a vertex ${\bf y} = (y_1,\dotso,y_{l+1})$ if $ x_i + y_i = f_{i-1}(x_1,y_1) $ for all $i$, $2\le i \le l+1$. In this paper we study the diameter of $D(q; {\bf f})$ in the special case of monomial digraphs $D(q; m,n)$: ${\bf f} = f_1$ and $f_1(x,y) = x^m y^n$ for some nonnegative integers $m$ and $n$.