Perron-Wright asymptotics and critical component processes for regular inhomogeneous random graphs

Abstract

We extend Wright's enumeration of connected labelled graphs with fixed surplus to irreducible critical finite type kernels and regular compact type kernels. Let $C_t(k,r)$ denote the total weight of connected labelled graphs with $k$ vertices and surplus $r$. Let $u>0$ satisfy $Ku=u$ and $\int u\,dμ=1$, and put $α=\int u^2\,dμ$ and $β=\int u^3\,dμ$. We prove that the rooted-tree radius $ρ$ is positive and real analytic near $1$, with $ρ(1)=1$ and $\logρ(t)=\frac{α^2}{2β}(t-1)^2+O(|t-1|^3)$, and that, for fixed $r\in\mathbb{Z}_{\ge0}$ and $0\le L < \infty$, $C_t(k,r)=w_rβ^{(r-1)/2}e^{-k}ρ(t)^{-k}k^{k+3r/2-2}\{1+O_{r,L}(k^{-1/2})\}$, uniformly for $|t-1|\le Lk^{-1/2}$, where $w_r$ is the classical Wright constant. At $t_n=1+λn^{-1/3}$, these asymptotics yield local size and surplus point-process limits for deterministic finite type models and annealed compact type Bollobas-Janson-Riordan models satisfying projective quadratic regularity. After rescaling component sizes by $β^{1/3}n^{-2/3}$, the limit is the Aldous process at parameter $αβ^{-2/3}λ$, and the corresponding type profiles concentrate at the Perron law $p(dx)=u(x)μ(dx)$. For every regular countable critical kernel, we construct graph sequences with growing finite supports and the same local limits, and identify the additive shift of the critical window caused by spectral perturbations of order $n^{-1/3}$.