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The planted densest subgraph detection problem refers to the task of testing whether in a given (random) graph there is a subgraph that is unusually dense. Specifically, we observe an undirected and unweighted graph on $n$ vertices. Under…

Data Structures and Algorithms · Computer Science 2024-05-06 Wasim Huleihel , Arya Mazumdar , Soumyabrata Pal

A paradigm that was successfully applied in the study of both pure and algorithmic problems in graph theory can be colloquially summarized as stating that "any graph is close to being the disjoint union of expanders". Our goal in this paper…

Combinatorics · Mathematics 2015-02-03 Guy Moshkovitz , Asaf Shapira

We prove that in all regular robust expanders $G$ every edge is asymptotically equally likely contained in a uniformly chosen perfect matching $M$. We also show that given any fixed matching or spanning regular graph $N$ in $G$, the random…

Combinatorics · Mathematics 2023-11-28 Bertille Granet , Felix Joos

Let S and T be vectors of positive integers with the same sum. We study the uniform distribution on the space of simple bipartite graphs with degree sequence S in one part and T in the other; equivalently, binary matrices with row sums S…

Combinatorics · Mathematics 2009-05-01 Catherine Greenhill , Brendan D. McKay

We show that every locally sparse graph contains a linearly sized expanding subgraph. For constants $c_1>c_2>1$, $0<\alpha<1$, a graph $G$ on $n$ vertices is called a $(c_1,c_2,\alpha)$-graph if it has at least $c_1n$ edges, but every…

Combinatorics · Mathematics 2017-05-04 Michael Krivelevich

The densest subgraph problem (DSG) aiming at finding an induced subgraph such that the average edge-weights of the subgraph is maximized, is a well-studied problem. However, when the input graph is a hypergraph, the existing notion of DSG…

Data Structures and Algorithms · Computer Science 2022-07-19 Yi Zhou , Shan Hu , Zimo Sheng

We revisit the classic problem of estimating the degree distribution moments of an undirected graph. Consider an undirected graph $G=(V,E)$ with $n$ vertices, and define (for $s > 0$) $\mu_s = \frac{1}{n}\cdot\sum_{v \in V} d^s_v$. Our aim…

Data Structures and Algorithms · Computer Science 2017-02-17 Talya Eden , Dana Ron , C. Seshadhri

An identifying code of a graph is a dominating set which uniquely determines all the vertices by their neighborhood within the code. Whereas graphs with large minimum degree have small domination number, this is not the case for the…

Combinatorics · Mathematics 2017-01-02 Florent Foucaud , Guillem Perarnau , Oriol Serra

A recent breakthrough of Behnezhad and Ghafari [FOCS 2024] and subsequent work of Assadi, Khanna, and Kiss [SODA 2025] gave algorithms for the fully dynamic $(1-\varepsilon)$-approximate maximum matching problem whose runtimes are…

Data Structures and Algorithms · Computer Science 2025-02-05 Kevin Pratt

A graph $G$ is said to be $p$-locally dense if every induced subgraph of $G$ with linearly many vertices has edge density at least $p$. A famous conjecture of Kohayakawa, Nagle, R\"odl, and Schacht predicts that locally dense graphs have,…

Combinatorics · Mathematics 2024-06-19 Domagoj Bradač , Benny Sudakov , Yuval Wigderson

We consider random sub-graphs of a fixed graph $G=(V,E)$ with large minimum degree. We fix a positive integer $k$ and let $G_k$ be the random sub-graph where each $v\in V$ independently chooses $k$ random neighbors, making $kn$ edges in…

Combinatorics · Mathematics 2014-05-12 Alan Frieze , Tony Johansson

Let $d,n\in \mathbb{N}$ be such that $d=\omega(1)$, and $d\le n^{1-a}$ for some constant $a>0$. Consider a $d$-regular graph $G=(V, E)$ and the random graph process that starts with the empty graph $G(0)$ and at each step $G(i)$ is obtained…

Combinatorics · Mathematics 2024-09-25 Sahar Diskin , Anna Geisler

In this paper, we study the problem of fast constructions of source-wise round-trip spanners in weighted directed graphs. For a source vertex set $S\subseteq V$ in a graph $G(V,E)$, an $S$-sourcewise round-trip spanner of $G$ of stretch $k$…

Data Structures and Algorithms · Computer Science 2023-02-21 Chun Jiang Zhu , Song Han , Kam-Yiu Lam

A graph $G$ is said to have \textit{bandwidth} at most $b$, if there exists a labeling of the vertices by $1,2,..., n$, so that $|i - j| \leq b$ whenever $\{i,j\}$ is an edge of $G$. Recently, B\"{o}ttcher, Schacht, and Taraz verified a…

Combinatorics · Mathematics 2015-03-17 Hao Huang , Choongbum Lee , Benny Sudakov

Let d = (d1, d2, ..., dn) be a vector of non-negative integers with even sum. We prove some basic facts about the structure of a random graph with degree sequence d, including the probability of a given subgraph or induced subgraph.…

Combinatorics · Mathematics 2010-11-30 Brendan D McKay

Designing distributed and scalable algorithms to improve network connectivity is a central topic in peer-to-peer networks. In this paper we focus on the following well-known problem: given an $n$-node $d$-regular network for $d=\Omega(\log…

Data Structures and Algorithms · Computer Science 2015-10-28 Zeyuan Allen-Zhu , Aditya Bhaskara , Silvio Lattanzi , Vahab Mirrokni , Lorenzo Orecchia

A seminal result of Koml\'os, S\'ark\"ozy, and Szemer\'edi states that any n-vertex graph G with minimum degree at least (1/2 + {\alpha})n contains every n-vertex tree T of bounded degree. Recently, Pham, Sah, Sawhney, and Simkin extended…

Combinatorics · Mathematics 2024-09-11 Paul Bastide , Clément Legrand-Duchesne , Alp Müyesser

We study the problem of maintaining robust and sparse overlay networks in fully distributed settings where nodes continuously join and leave the system. This scenario closely models real-world unstructured peer-to-peer networks, where…

Distributed, Parallel, and Cluster Computing · Computer Science 2025-09-16 Antonio Cruciani

While in many graph mining applications it is crucial to handle a stream of updates efficiently in terms of {\em both} time and space, not much was known about achieving such type of algorithm. In this paper we study this issue for a…

Data Structures and Algorithms · Computer Science 2015-09-23 Sayan Bhattacharya , Monika Henzinger , Danupon Nanongkai , Charalampos E. Tsourakakis

We investigate the distributed complexity of maximal matching and maximal independent set (MIS) in hypergraphs in the LOCAL model. A maximal matching of a hypergraph $H=(V_H,E_H)$ is a maximal disjoint set $M\subseteq E_H$ of hyperedges and…

Data Structures and Algorithms · Computer Science 2022-11-04 Alkida Balliu , Sebastian Brandt , Fabian Kuhn , Dennis Olivetti