Shallow brambles

TL;DR

This paper investigates bounded-radius variants of classical graph parameters within classes of graphs with polynomial expansion, establishing their polynomial relationships and bounds.

Contribution

It introduces bounded-radius variants of bramble number, linkedness, and well-linkedness, proving their polynomial relationships and bounds in polynomial expansion graph classes.

Findings

Bounded-radius parameters are pairwise polynomially related.

In polynomial expansion classes, these parameters are uniformly bounded by a polynomial in radius.

The study extends classical graph parameters to localized variants with polynomial bounds.

Abstract

A graph class $\mathcal{C}$ has polynomial expansion if there is a polynomial function $f$ such that for every graph $G\in \mathcal{C}$, each of the depth-$r$ minors of $G$ has average degree at most $f(r)$. In this note, we study bounded-radius variants of some classical graph parameters such as bramble number, linkedness and well-linkedness, and we show that they are pairwise polynomially related. Furthermore, in a monotone graph class with polynomial expansion they are all uniformly bounded by a polynomial in $r$.