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Vertex-minor universality of a random graph

Ting-Wei Chao, Zixuan Xu

Abstract

Given a graph $G$ and a vertex $v\in V(G)$, a local complementation at $v$ on $G$ is an operation that replaces the induced graph on the neighborhood of $v$ by its complement. A graph $H$ is a vertex-minor if $H$ can be obtained from $G$ by a sequence of vertex deletions and local complementation. A graph is said to be $k$-vertex-minor universal if it contains every $k$-vertex graph on any $k$-subset of vertices as a vertex minor. Previously, Ascoli--Fredrickson--Fredrickson--McFarland--Post proved that with high probability $G(n,1/2)$ is $Ω(\sqrt{n})$-vertex-minor universal. Furthermore, they conjectured that with high probability $G(n,p)$ and $G(n,1-p)$ are $Ω(p\sqrt{n})$-vertex-minor universal for all $ω(1/\sqrt{n})\le p\le 1/2$. In this short note, we confirm this conjecture up to an extra logarithm factor and show that this is true with probability $1-2^{-Ω(p^2n)}$ if $Ω(\log n/\sqrt{n})\le p\le 1/2$.

Vertex-minor universality of a random graph

Abstract

Given a graph and a vertex , a local complementation at on is an operation that replaces the induced graph on the neighborhood of by its complement. A graph is a vertex-minor if can be obtained from by a sequence of vertex deletions and local complementation. A graph is said to be -vertex-minor universal if it contains every -vertex graph on any -subset of vertices as a vertex minor. Previously, Ascoli--Fredrickson--Fredrickson--McFarland--Post proved that with high probability is -vertex-minor universal. Furthermore, they conjectured that with high probability and are -vertex-minor universal for all . In this short note, we confirm this conjecture up to an extra logarithm factor and show that this is true with probability if .
Paper Structure (4 sections, 5 theorems, 38 equations)

This paper contains 4 sections, 5 theorems, 38 equations.

Key Result

Theorem 1.1

For a positive integer $k$ and $G\sim G(n,1/2)$, if $n\geqslant (1+C)\frac{1}{2\log_2(4/3)}k^2$ for some $C>0$, then $G$ is $k$-vertex-minor universal with probability at least $1-2^{-(1+o(1))Ck^2/2}$.

Theorems & Definitions (16)

  • Theorem 1.1: AFFMP26
  • Conjecture 1.2: AFFMP26
  • Theorem 1.3
  • Lemma 2.1
  • proof
  • Theorem 2.2
  • Remark 2.3
  • Lemma 3.1
  • proof
  • Claim 3.2
  • ...and 6 more