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We study first passage percolation on the configuration model (CM) having power-law degrees with exponent $\tau\in [1,2)$. To this end we equip the edges with exponential weights. We derive the distributional limit of the minimal weight of…

Probability · Mathematics 2009-05-28 Shankar Bhamidi , Remco van der Hofstad , Gerard Hooghiemstra

Inspired by studies on the airports' network and the physical Internet, we propose a general model of weighted networks via an optimization principle. The topology of the optimal network turns out to be a spanning tree that minimizes a…

Physics and Society · Physics 2009-11-11 Marc Barthelemy , Alessandro Flammini

Given $D$ and $\gamma>0$, whenever $c>0$ is sufficiently small and $n$ sufficiently large, if $\mathcal{G}$ is a family of $D$-degenerate graphs of individual orders at most $n$, maximum degrees at most $\tfrac{cn}{\log n}$, and total…

Combinatorics · Mathematics 2022-04-19 Peter Allen , Julia Böttcher , Jan Hladký , Diana Piguet

Fractional (hyper-)graph theory is concerned with the specific problems that arise when fractional analogues of otherwise integer-valued (hyper-)graph invariants are considered. The focus of this paper is on fractional edge covers of…

Discrete Mathematics · Computer Science 2023-09-25 Georg Gottlob , Matthias Lanzinger , Reinhard Pichler , Igor Razgon

A pair $(u, v)$ of (not necessarily distinct) vertices in a directed graph $D$ is called a reachable pair if there exists a directed path from $u$ to $v$. We define the weight of $D$ to be the number of reachable pairs of $D$, which equals…

Combinatorics · Mathematics 2020-05-27 Eric Swartz , Nicholas J. Werner

The Multicut problem asks for a minimum cut separating certain pairs of vertices: formally, given a graph $G$ and demand graph $H$ on a set $T\subseteq V(G)$ of terminals, the task is to find a minimum-weight set $C$ of edges of $G$ such…

Computational Complexity · Computer Science 2025-04-16 Jacob Focke , Florian Hörsch , Shaohua Li , Dániel Marx

Flow sparsification is a classic graph compression technique which, given a capacitated graph $G$ on $k$ terminals, aims to construct another capacitated graph $H$, called a flow sparsifier, that preserves, either exactly or approximately,…

Data Structures and Algorithms · Computer Science 2024-09-09 Syamantak Das , Nikhil Kumar , Daniel Vaz

We give a new, systematic proof for a recent result of Larry Guth and thus also extend the result to a setting with several families of varieties: For any integer $D\geq 1$ and any collection of sets $\Gamma_1,\ldots,\Gamma_j$ of low-degree…

We provide an explicit solution of the problem of level-set percolation for multivariate Gaussians defined in terms of weighted graph Laplacians on complex networks. The solution requires an analysis of the heterogeneous micro-structure of…

Disordered Systems and Neural Networks · Physics 2024-04-09 Reimer Kuehn

Given a partition ${\mathcal V}=(V_1, \ldots,V_m)$ of the vertex set of a graph $G$, an {\em independent transversal} (IT) is an independent set in $G$ that contains one vertex from each $V_i$. A {\em fractional IT} is a non-negative real…

Combinatorics · Mathematics 2017-03-10 Ron Aharoni , Irina Gorelik

We examine the stability of a 1D electrical transmission line in the simultaneous presence of PT-symmetry and fractionality. The array contains a binary gain/loss distribution $\gamma_{n}$ and a fractional Laplacian characterized by a…

Pattern Formation and Solitons · Physics 2023-08-09 Mario I. Molina

The terminal backup problems (Anshelevich and Karagiozova (2011)) form a class of network design problems: Given an undirected graph with a requirement on terminals, the goal is to find a minimum cost subgraph satisfying the connectivity…

Data Structures and Algorithms · Computer Science 2020-08-25 Hiroshi Hirai , Motoki Ikeda

The computation of electrical flows is a crucial primitive for many recently proposed optimization algorithms on weighted networks. While typically implemented as a centralized subroutine, the ability to perform this task in a fully…

Distributed, Parallel, and Cluster Computing · Computer Science 2019-07-01 Luca Becchetti , Vincenzo Bonifaci , Emanuele Natale

We study the complete graph equipped with a topology induced by independent and identically distributed edge weights. The focus of our analysis is on the weight W_n and the number of edges H_n of the minimal weight path between two distinct…

Probability · Mathematics 2015-06-12 Maren Eckhoff , Jesse Goodman , Remco van der Hofstad , Francesca R. Nardi

In many real world networks, there already exists a (not necessarily optimal) $k$-partitioning of the network. Oftentimes, one aims to find a $k$-partitioning with a smaller cut value for such networks by moving only a few nodes across…

Data Structures and Algorithms · Computer Science 2024-02-26 Majid Behbahani , Mina Dalirrooyfard , Elaheh Fata , Yuriy Nevmyvaka

The cochromatic number $Z(G)$ of a graph $G$ is the fewest number of colors needed to color the vertices of $G$ so that each color class is a clique or an independent set. In a fractional cocoloring of $G$ a non-negative weight is assigned…

Combinatorics · Mathematics 2019-06-14 John Gimbel , André Kündgen , Michael Molloy

The analysis of networks, aimed at suitably defined functionality, often focuses on partitions into subnetworks that capture desired features. Chief among the relevant concepts is a 2-partition, that underlies the classical Cheeger…

Discrete Mathematics · Computer Science 2020-09-29 Fariba Ariaei , Zahra Askarzadeh , Yongxin Chen , Tryphon T. Georgiou

In this paper we consider several problems concerning packet routing in distributed systems. Each problem is formulated using terms from Graph Theory and for each problem we present efficient, novel, algorithmic techniques for computing…

Data Structures and Algorithms · Computer Science 2009-06-19 Mugurel Ionut Andreica , Nicolae Tapus

The dichromatic number of a graph $G$ is the maximum integer $k$ such that there exists an orientation of the edges of $G$ such that for every partition of the vertices into fewer than $k$ parts, at least one of the parts must contain a…

Combinatorics · Mathematics 2022-09-20 Bojan Mohar , Hehui Wu

Given a large edge-capacitated network $G$ and a subset of $k$ vertices called terminals, an (exact) flow sparsifier is a small network $G'$ that preserves (exactly) all multicommodity flows that can be routed between the terminals. Flow…

Data Structures and Algorithms · Computer Science 2022-08-04 Robert Krauthgamer , Ron Mosenzon