arXiv subjects

Alberto M. Campos

Publications and source records attributed to Alberto M. Campos.

6 recordsLinked to original sources

arXiv2026

The probability of connection between two vertices cannot be monotone with the distance for Bernoulli Percolation on transitive graphs

A popular question in Bernoulli percolation models is if the probability of connection between two vertices in a transitive graph decays monotonically with the distance between these two vertices. For example, on the square lattice is an open question to prove that the probability of the origin being connected to the vertex $(0,n)$ is monotone in $n$. In this short note, we exhibit an example of a transitive graph in which the probability of connection between vertices does not necessarily decay as the distance of those vertices grows. We also define a critical point for percolation in $\mathbb{Z}^d$, in which using a generalization of the percolation process it is possible to see the same phenomena happening in the embedding of $\mathbb{Z}^d$ over $\mathbb{R}^d$.

math.PR↗

arXiv2025

Hydrodynamic limit for repeated averages on the complete graph

We establish a hydrodynamical limit for the averaging process on the complete graph with N vertices, showing that, after a timescale of order N, the empirical distribution of opinions converges to a unique measure. Moreover, if the initial distribution is absolutely continuous concerning the Lebesgue measure, the limiting measure remains absolutely continuous and its density satisfies a non-diffusive differential equation, that resembles the Smoluchowski coagulation equation.

math.PR↗

arXiv2024

First order of the renewal covering of the natural numbers

This paper introduces a new type of covering process that covers the set of natural numbers using renewal processes as objects. Inspired by the behavior of prime numbers, the model in each step finds the smallest vacant point, $k$, and place, starting in $k$, a renewal process with a step distribution given by a geometric random variable with parameter $\frac{1}{k}$. The model depends on its entire past, and small perturbations in its initial value can lead to very different outcomes. Here, we expose a technique that finds the first-order limit behavior for the number of objects placed until $n$, which exhibits intriguing similarities to prime number distributions, having a concentration around $n\log{n}$.

math.PR↗

arXiv2024

Covering Distributions

In this article, we study a covering process of the discrete one-dimensional torus that uses connected arcs of random sizes in the covering. More precisely, fix a distribution μon \mathbb{N}, and for every n\geq 1 we will cover the torus \mathbb{Z}/n\mathbb{Z} as follows: at each time step, we place an arc with a length distributed as μand a uniform starting point. Eventually, the space will be covered entirely by these arcs. Changing the arc length distribution μcan potentially change the limiting behavior of the covering time. Here, we expose four distinct phases for the fluctuations of the cover time in the limit. These phases can be informally described as the Gumbel phase, the compactly support phase, the pre-exponential phase, and the exponential phase. Furthermore, we expose a continuous-time cover process that works as a limit distribution within the compactly support phase.

math.PR↗

arXiv2023

Random walk in a rotational environment

We define a random walk of a particle in $\mathbb{R}^3$ where the space is rotating. The particle is not glued to the space and will collide with it at random times, resulting in changes in its velocity and direction. After many collisions, the random walk starts to have some asymptotic behaviors inherited from the movement of space. The paper will find the limit movement of the particle, and explain how the randomness of the random walk gives rise to the particle asymptotic deterministic movement.

math.PR↗

arXiv2022

Truncation of long-range percolation model with square non-summable interactions

We consider some problems related to the truncation question in long-range percolation. It is given probabilities that certain long-range oriented bonds are open; assuming that this probabilities are not summable, we ask if the probability of percolation is positive when we truncate the graph, disallowing bonds of range above a possibly large but finite threshold. This question is still open if the set of vertices is $\Z^2$. We give some conditions in which the answer is affirmative. One of these results generalize the previous result in [Alves, Hilário, de Lima, Valesin, Journ. Stat. Phys. {\bf 122}, 972 (2017)].

math.PR↗