## Bernoulli

• Bernoulli
• Volume 19, Number 2 (2013), 363-386.

### Weak disorder in the stochastic mean-field model of distance II

#### Abstract

In this paper, we study the complete graph $K_{n}$ with $n$ vertices, where we attach an independent and identically distributed (i.i.d.) weight to each of the $n(n-1)/2$ edges. We focus on the weight $W_{n}$ and the number of edges $H_{n}$ of the minimal weight path between vertex $1$ and vertex $n$.

It is shown in (Ann. Appl. Probab. 22 (2012) 29–69) that when the weights on the edges are i.i.d. with distribution equal to that of $E^{s}$, where $s>0$ is some parameter, and $E$ has an exponential distribution with mean $1$, then $H_{n}$ is asymptotically normal with asymptotic mean $s\log n$ and asymptotic variance $s^{2}\log n$. In this paper, we analyze the situation when the weights have distribution $E^{-s}$, $s>0$, in which case the behavior of $H_{n}$ is markedly different as $H_{n}$ is a tight sequence of random variables. More precisely, we use the method of Stein–Chen for Poisson approximations to show that, for almost all $s>0$, the hopcount $H_{n}$ converges in probability to the nearest integer of $s+1$ greater than or equal to $2$, and identify the limiting distribution of the recentered and rescaled minimal weight. For a countable set of special $s$ values denoted by $\mathcal{S}=\{s_{j}\}_{j\geq2}$, the hopcount $H_{n}$ takes on the values $j$ and $j+1$ each with positive probability.

#### Article information

Source
Bernoulli, Volume 19, Number 2 (2013), 363-386.

Dates
First available in Project Euclid: 13 March 2013

https://projecteuclid.org/euclid.bj/1363192031

Digital Object Identifier
doi:10.3150/11-BEJ402

Mathematical Reviews number (MathSciNet)
MR3037157

Zentralblatt MATH identifier
1279.60018

#### Citation

Bhamidi, Shankar; van der Hofstad, Remco; Hooghiemstra, Gerard. Weak disorder in the stochastic mean-field model of distance II. Bernoulli 19 (2013), no. 2, 363--386. doi:10.3150/11-BEJ402. https://projecteuclid.org/euclid.bj/1363192031

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