An Euclidean first-passage percolation (FPP) model describing the competing growth between $k$ different types of infection is considered. We focus on the long time behavior of this multi-type growth process and we derive multi-type shape results related to its morphology.
This paper studies the first passage percolation (FPP) model: each edge in the cubic lattice is assigned a random passage time, and consideration is given to the behavior of the percolation region $B(t)$, which consists of those vertices that can be reached from the origin within a time $t > 0$. Cox and Durrett showed the shape theorem for the percolation region, saying that the normalized region $B(t)/t$ converges to some limit shape $\mathcal{B}$. This paper introduces a general FPP model defined on crystal lattices, and shows the monotonicity of the limit shapes under covering maps, thereby…
We study first passage percolation (FPP) with stationary edge weights on Cayley graphs of finitely generated virtually nilpotent groups. Previous works of Benjamini-Tessera and Cantrell-Furman show that scaling limits of such FPP are given by Carnot-Carathéodory metrics on the associated graded nilpotent Lie group. We show a converse, i.e. that for any Cayley graph of a finitely generated nilpotent group, any Carnot-Carathéodory metric on the associated graded nilpotent Lie group is the scaling limit of some FPP with stationary edge weights on that graph. Moreover, for any Cayley graph of any …
Recently, many results have been established drawing a parallel between Bernoulli percolation and models given by levels of smooth Gaussian fields with unbounded, strongly decaying correlation. In a previous work with D. Gayet , we started to extend these analogies by adapting the first basic results of classical first passage percolation in this new framework: positivity of the time constant and the ball-shape theorem. In the present paper, we present a proof inspired by Kesten of other basic properties of the new FPP model: an upper bound on the variance in the FPP pseudometric given by the …
We study Bernoulli first-passage percolation (FPP) on the triangular lattice $\mathbb{T}$ in which sites have 0 and 1 passage times with probability $p$ and $1-p$, respectively. Denote by $\mathcal {C}_{\infty}$ the infinite cluster with 0-time sites when $p>p_c$, where $p_c=1/2$ is the critical probability. Denote by $T(0,\mathcal {C}_{\infty})$ the passage time from the origin 0 to $\mathcal {C}_{\infty}$. First we obtain explicit limit theorem for $T(0,\mathcal {C}_{\infty})$ as $p\searrow p_c$. The proof relies on the limit theorem in the critical case, the critical exponent for correlatio…
It has been well known for a long time that the height function of random lozenge tilings of large domains follow a law of large number and possible limits called dimer limit shapes are well understood. For the next order, it is expected that fluctuations behave like version of a Gaussian Free field, at least away from some special "frozen" regions. However despite being one of the main questions in the domain for 20 years, only special cases have been obtained. In this paper we show that for any specified limit shape with no frozen region, one can construct a sequence of domains whose height …
First Passage Percolation on Inhomogeneous Random Graphs
本文研究了非齐次随机图上的首次通过渗流问题。我们研究的随机图模型G(n,kappa)是Bollobás,Janson和Riordan提出的模型,其中每个顶点都有一个来自类型空间S的类型,边概率是独立的,但依赖于端顶点的类型。每个边被赋予独立的指数权重。我们确定的最短路径之间的统一选择的顶点在巨大的组件的重量分布,并表明,跳数,即边缘的数量在这个最小的重量路径,适当规范化遵循中心极限定理。我们处理的情况下,lambda(n)->lambda是有限的或无限的,假设一个顶点的邻居lambda(n)的平均数量是独立的类型。本文推广了Bhamidi,van der Hofstad和Hooghiemstra在Erdos-Renyi图上研究FPP的文章.
We consider geodesics for first passage percolation (FPP) on $\mathbb{Z}^d$ with iid passage times. As has been common in the literature, we assume that the FPP system satisfies certain basic properties conjectured to be true, and derive consequences from these properties. The assumptions are roughly as follows: (i) the fluctuation scale $σ(r)$ of the passage time on scale $r$ grows approximately as a positive power $r^χ$, in the sense that two natural definitions of $σ(r)$ and $χ$ yield the same value $χ$, and (ii) the limit shape boundary has curvature uniformly bounded away from 0 and $\inf…
We consider a model of first passage percolation (FPP) where the nearest-neighbor edges of the standard two-dimensional Euclidean lattice are equipped with random variables. These variables are i.i.d.\, nonnegative, continuous, and have a finite moment generating function in a neighborhood of $0$. We derive consequences about transverse increments of passage times, assuming the model satisfies certain properties. Approximately, the assumed properties are the following: We assume that the standard deviation of the passage time on scale $r$ is of some order $σ(r)$, and $\left\{σ(r), r > 0\right\…
We study a particular model of a random medium, called the orthant model, in general dimensions $d\ge 2$. Each site $x\in \Z^d$ independently has arrows pointing to its positive neighbours $x+e_i$, $i=1,\dots, d$ with probability $p$ and otherwise to its negative neighbours $x-e_i$, $i=1,\dots, d$ (with probability $1-p$). We prove a shape theorem for the set of sites reachable by following arrows, starting from the origin, when $p$ is large. The argument uses subadditivity, as would be expected from the shape theorems arising in the study of first passage percolation. The main difficulty to o…
We consider a one-dimensional discrete-space birth process with a bounded number of particle per site. Under the assumptions of the finite range of interaction, translation invariance, and non-degeneracy, we prove a shape theorem. We also derive a limiting estimate and an exponential estimate on the fluctuations of the position of the rightmost particle.
In this work, we prove a shape theorem for Poisson cylinders and give a power law bound on surface fluctuations. We prove that for any $a \in (1/2, 1)$, conditioned on the origin being in the set of cylinders, every point in this set, whose Euclidean norm is less than $R$, lies at an internal distance less than $R+O(R^a)$ from the origin.
We prove a shape theorem and derive a variational formula for the limiting quenched Lyapunov exponent and the Green's function of random walk in a random potential on a square lattice of arbitrary dimension and with an arbitrary finite set of steps. The potential is a function of a stationary environment and the step of the walk. This potential is subject to a moment assumption whose strictness is tied to the mixing of the environment. Our setting includes directed and undirected polymers, random walk in static and dynamic random environment, and, when the temperature is taken to zero, our res…
We present a general approach to study a class of random growth models in $n$-dimensional Euclidean space. These models are designed to capture basic growth features which are expected to manifest at the mesoscopic level for several classical self-interacting processes originally defined at the microscopic scale. It includes once-reinforced random walk with strong reinforcement, origin-excited random walk, and few others, for which the set of visited vertices is expected to form a "limiting shape". We prove an averaging principle that leads to such shape theorem. The limiting shape can be comp…
我们考虑以下相互作用粒子系统:有一个“气体”的粒子,其中每个执行一个连续的时间简单的随机游动的d维晶格。这些粒子被称为A粒子,它们相互独立地运动。我们假设系统开始时每个格点x上有一个泊松数的粒子,不同x的i.i.d.上的粒子数。此外,还有有限个B粒子,它们可以像A粒子一样进行连续时间的简单随机游动。A粒子和B粒子分别被解释为健康或受感染的个体。B粒子彼此独立运动。唯一的相互作用是,当B粒子和A粒子重合时,后者瞬间变成B粒子。设B(t)是B粒子在[0,t]期间访问的站点的集合。我们证明了B(t)随时间线性增长并具有渐近形状;更确切地说,存在一个非随机凸紧集B_0,使得几乎必然地,对所有0 < a <1,(1-a)tB_0包含在B(t)中,并且B(t)最终包含在(1+a)tB_0中。
Random growth models are fundamental objects in modern probability theory, have given rise to new mathematics, and have numerous applications, including tumor growth and fluid flow in porous media. In this article, we introduce some of the typical models and the basic analytical questions and properties, like existence of asymptotic shapes, fluctuations of infection times, and relations to particle systems. We then specialize to models built on percolation (first-passage percolation and last-passage percolation) and give a self-contained treatment of the shape theorem, the subadditive ergodic …
The $β$-Delaunay tessellation in $\mathbb{R}^{d-1}$ is a generalization of the classical Poisson-Delaunay tessellation. As a first result of this paper we show that the shape of a weighted typical cell of a $β$-Delaunay tessellation, conditioned on having large volume, is close to the shape of a regular simplex in $\mathbb{R}^{d-1}$. This generalizes earlier results of Hug and Schneider about the typical (non-weighted) Poisson-Delaunay simplex. Second, the asymptotic behaviour of the volume of weighted typical cells in high-dimensional $β$-Delaunay tessellation is analysed, as $d\to\infty$. In…
We establish quantitative spherical shape theorems for rotor-router aggregation and abelian sandpile growth on the graphical Sierpinski gasket ($SG$) when particles are launched from the corner vertex. In particular, the abelian sandpile growth problem is exactly solved via a recursive construction of self-similar sandpile tiles. We show that sandpile growth and patterns exhibit a $(2\cdot 3^n)$-periodicity as a function of the initial mass. Moreover, the cluster explodes---increments by more than 1 in radius---at periodic intervals, a phenomenon not seen on $\mathbb{Z}^d$ or trees. We explici…