English

Embedding theorems for random graphs with specified degrees

Combinatorics 2024-12-11 v2

Abstract

Given an n×nn\times n symmetric matrix W[0,1][n]×[n]W\in [0,1]^{[n]\times [n]}, let G(n,W)\mathcal{G}(n,W) be the random graph obtained by independently including each edge jkjk with probability WjkW_{jk}. Given a degree sequence d=(d1,,dn){\bf d}=(d_1,\ldots, d_n), let G(n,d)\mathcal{G}(n,{\bf d}) denote a uniformly random graph with degree sequence d{\bf d}. We couple G(n,W)\mathcal{G}(n,W) and G(n,d)\mathcal{G}(n,{\bf d}) together so that a.a.s. G(n,W)\mathcal{G}(n,W) is a subgraph of G(n,d)\mathcal{G}(n,{\bf d}), where WW is some function of d{\bf d}. Let Δ(d)\Delta({\bf d}) denote the maximum degree in d{\bf d}. Our coupling result is optimal when Δ(d)2d1\Delta({\bf d})^2\ll \|{\bf d}\|_1, i.e.\ WijW_{ij} is asymptotic to P(ijG(n,d))\mathbb{P}(ij\in \mathcal{G}(n,{\bf d})) for every i,j[n]i,j\in [n]. We also have coupling results for d{\bf d} that are not constrained by the condition Δ(d)2d1\Delta({\bf d})^2\ll \|{\bf d}\|_1. For such d{\bf d} our coupling result is still close to optimal, in the sense that WijW_{ij} is asymptotic to P(ijG(n,d))\mathbb{P}(ij\in \mathcal{G}(n,{\bf d})) for most pairs i,j[n]i,j\in [n].

Keywords

Cite

@article{arxiv.2302.09729,
  title  = {Embedding theorems for random graphs with specified degrees},
  author = {Pu Gao and Yuval Ohapkin},
  journal= {arXiv preprint arXiv:2302.09729},
  year   = {2024}
}