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The celebrated dependent random choice lemma states that in a bipartite graph an average vertex (weighted by its degree) has the property that almost all small subsets $S$ in its neighborhood has common neighborhood almost as large as in…

Combinatorics · Mathematics 2022-01-27 Tao Jiang , Sean Longbrake

Classes with bounded expansion, which generalise classes that exclude a topological minor, have recently been introduced by Ne\v{s}et\v{r}il and Ossona de Mendez. These classes are defined by the fact that the maximum average degree of a…

Combinatorics · Mathematics 2012-05-21 Jaroslav Nešetřil , Patrice Ossona de Mendez , David R. Wood

Expander graphs, due to their mixing properties, are useful in many algorithms and combinatorial constructions. One can produce an expander graph with high probability by taking a random graph (e.g., the union of $d$ random bijections for a…

Combinatorics · Mathematics 2024-05-30 Geoffroy Caillat-Grenier

We prove that the $\alpha$-expansion algorithm for MAP inference always returns a globally optimal assignment for Markov Random Fields with Potts pairwise potentials, with a catch: the returned assignment is only guaranteed to be optimal…

Machine Learning · Statistics 2021-06-16 Hunter Lang , David Sontag , Aravindan Vijayaraghavan

A graph is said to be $\mathcal{H}(n, \Delta)$-universal if it contains every graph on $n$ vertices with maximum degree at most $\Delta$. Using a `matching-based' embedding technique introduced by Alon and F\"uredi, Dellamonica, Kohayakawa,…

Combinatorics · Mathematics 2017-07-26 Asaf Ferber , Rajko Nenadov

A common model for social networks are Geometric Inhomogeneous Random Graphs (GIRGs), in which vertices draw a random position in some latent geometric space, and the probability of two vertices forming an edge depends on their geometric…

Social and Information Networks · Computer Science 2025-06-25 Marc Kaufmann , Johannes Lengler , Ulysse Schaller , Konstantin Sturm

Recently, Brandt et al. [STOC'16] proved a lower bound for the distributed Lov\'asz Local Lemma, which has been conjectured to be tight for sufficiently relaxed LLL criteria by Chang and Pettie [FOCS'17]. At the heart of their result lies a…

Distributed, Parallel, and Cluster Computing · Computer Science 2019-02-27 Sebastian Brandt

This write-up contains some minor results and notes related to our work [HQ15] (some of them already known in the literature). In particular, it shows the following: - We show that a graph with polynomial expansion have sublinear…

Computational Geometry · Computer Science 2016-03-11 Sariel Har-Peled , Kent Quanrud

Motivated by low energy consumption in geographic routing in wireless networks, there has been recent interest in determining bounds on the length of edges in the Delaunay graph of randomly distributed points. Asymptotic results are known…

Computational Geometry · Computer Science 2011-08-23 Esther M. Arkin , Antonio Fernandez Anta , Joseph S. B. Mitchell , Miguel A. Mosteiro

We present a new algorithm for improving lower bounds on $ex(n;\{C_3,C_4\})$, the maximum size (number of edges) of an $n$-vertex graph of girth at least 5. The core of our algorithm is a variant of a hill-climbing heuristic introduced by…

Combinatorics · Mathematics 2025-08-08 Jan Goedgebeur , Jorik Jooken , Gwenaël Joret , Tibo Van den Eede

How does the chromatic number of a graph chosen uniformly at random from all graphs on $n$ vertices behave? This quantity is a random variable, so one can ask (i) for upper and lower bounds on its typical values, and (ii) for bounds on how…

Combinatorics · Mathematics 2023-08-21 Annika Heckel , Oliver Riordan

Edge expansion is a parameter indicating how well-connected a graph is. It is useful for designing robust networks, analysing random walks or information flow through a network and is an important notion in theoretical computer science.…

Probability · Mathematics 2026-01-12 Colin McDiarmid , Katarzyna Rybarczyk , Fiona Skerman , Małgorzata Sulkowska

In this article we present an algorithm to compute bounds on the marginals of a graphical model. For several small clusters of nodes upper and lower bounds on the marginal values are computed independently of the rest of the network. The…

Artificial Intelligence · Computer Science 2011-06-27 B. Kappen , M. Leisink

In this paper we give new bounds on the bisection width of random 3-regular graphs on $n$ vertices. The main contribution is a new lower bound of $0.103295n$ based on a first moment method together with a structural analysis of the graph,…

Probability · Mathematics 2023-06-13 Lyuben Lichev , Dieter Mitsche

Goodman proved that the sum of the number of triangles in a graph on $n$ nodes and its complement is at least $n^3/24$; in other words, this sum is minimized, asymptotically, by a random graph with edge density $1/2$. Erd\H{o}s conjectured…

Combinatorics · Mathematics 2019-12-09 Endre Csóka , Tamás Hubai , László Lovász

Let $A_1, A_2, \ldots, A_n$ be events in a sample space. Given the probability of the intersection of each collection of up to $k+1$ of these events, what can we say about the probability that at least $r$ of the events occur? This question…

Combinatorics · Mathematics 2025-05-20 Ilan Adler , Richard M. Karp , Sheldon M. Ross

For a graph $G$ on $n$ vertices, naively sampling the position of a random walk of at time $t$ requires work $\Omega(t)$. We desire local access algorithms supporting $\text{position}(G,s,t)$ queries, which return the position of a random…

Data Structures and Algorithms · Computer Science 2021-02-16 Amartya Shankha Biswas , Edward Pyne , Ronitt Rubinfeld

Mossel and Ross (2019) introduce the shotgun assembly problem for random graphs: what radius $R$ ensures that the random graph $G$ can be uniquely recovered from its list of rooted $R$-neighborhoods, with high probability? Here we consider…

Probability · Mathematics 2025-12-03 Brice Huang , Elchanan Mossel , Nike Sun , Claire Zhang , Leqi Zhou

For a unimodular random graph $(G,\rho)$, we consider deformations of its intrinsic path metric by a (random) weighting of its vertices. This leads to the notion of the conformal growth exponent of $(G,\rho)$, which is the best asymptotic…

Probability · Mathematics 2020-06-02 James R. Lee

The asymptotic spectrum of graphs, introduced by Zuiddam (arXiv:1807.00169, 2018), is the space of graph parameters that are additive under disjoint union, multiplicative under the strong product, normalized and monotone under homomorphisms…

Combinatorics · Mathematics 2019-03-06 Péter Vrana