Spanning trees with large maximum degrees

TL;DR

This paper extends a fundamental graph theory result to larger maximum degrees, establishing near-optimal minimum degree conditions for spanning trees with high maximum degrees in both deterministic and random graphs.

Contribution

It generalizes the Komlós–Sárközy–Szemerédi theorem to trees with degrees up to roughly n/ log n, providing asymptotically optimal minimum degree thresholds.

Findings

Minimum degree condition for spanning trees with high maximum degree

Extension of classical result to trees with degree up to a n/ log n

Results applicable to both deterministic and random graphs

Abstract

The celebrated result of Koml\'os, S\'ark\"ozy, and Szemer\'edi states that for any $\varepsilon>0$, there exists $0<c<1$, such that for all sufficiently large $n$, every $n$-vertex graph $G$ with $\delta(G)\geq(1/2+\varepsilon)n$ contains every $n$-vertex tree with maximum degree at most $cn/\log n$. This is best possible up to the value of $c$. In this paper, we extend this result to trees with higher maximum degrees, and prove that for $\Delta\gg n/\log n$, roughly speaking, $\delta(G)\geq n-n^{1-(1+o(1))\Delta/n}$ is the asymptotically optimal minimum degree condition which guarantees that $G$ contains every $n$-vertex spanning tree with maximum degree at most $\Delta$. We also prove the corresponding statements in the random graph setting.