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It is proved that for infinitely many positive integers n, there exists a circulant graph of order n whose Weisfeiler-Leman dimension is at least c\sqrt{log n} for some positive constant c not depending on n.

Combinatorics · Mathematics 2025-12-16 Yulai Wu , Qing Ren , Ilia Ponomarenko

We establish sharp universal upper bounds on the length of the shortest closed geodesic on a punctured sphere with three or four ends endowed with a complete Riemannian metric of finite area. These sharp curvature-free upper bounds are…

Differential Geometry · Mathematics 2020-09-23 Antonia Jabbour , Stéphane Sabourau

Alexandrov's estimate states that if $\Omega$ is a bounded open convex domain in ${\mathbb R}^n$ and $u:\bar \Omega\to {\mathbb R}$ is a convex solution of the Monge-Ampere equation $\det D^2 u = f$ that vanishes on $\partial \Omega$, then…

Analysis of PDEs · Mathematics 2024-03-12 Charles Griffin , Kennedy Obinna Idu , Robert L. Jerrard

Let $G$ be a graph on $n$ vertices of maximum degree $\Delta$. We show that, for any $\delta > 0$, the down-up walk on independent sets of size $k \leq (1-\delta)\alpha_c(\Delta)n$ mixes in time $O_{\Delta,\delta}(k\log{n})$, thereby…

Data Structures and Algorithms · Computer Science 2023-05-11 Vishesh Jain , Marcus Michelen , Huy Tuan Pham , Thuy-Duong Vuong

De Loera, O'Neill and Wilburne introduced a general model for random numerical semigroups in which each positive integer is chosen independently with some probability p to be a generator, and proved upper and lower bounds on the expected…

Commutative Algebra · Mathematics 2025-07-23 Tristram Bogart , Santiago Morales

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

Frameproof codes have been extensively studied for many years due to their application in copyright protection and their connection to extremal set theory. In this paper, we investigate upper bounds on the cardinality of wide-sense…

Combinatorics · Mathematics 2024-02-09 Yuhao Zhao , Xiande Zhang

We consider the top tree compression scheme introduced by Bille et al. [ICALP 2013] and construct an infinite family of trees on $n$ nodes labeled from an alphabet of size $\sigma$, for which the size of the top DAG is…

Data Structures and Algorithms · Computer Science 2018-01-04 Bartłomiej Dudek , Paweł Gawrychowski

Improving a recent result of Fundikwa, Mazorodze, and Mukwembi, we show that $d \leq (2n-3)/5$ for every connected $C_4$-free graph of order $n$, diameter $d$, and edge-connectivity at least $3$, which is best possible up to a small…

Combinatorics · Mathematics 2021-12-17 Vanessa Hiebeler , Johannes Pardey , Dieter Rautenbach

We consider the problem of lower bounding a generalized Minkowski measure of subsets of a convex body with a log-concave probability measure, conditioned on the set size. A bound is given in terms of diameter and set size, which is sharp…

Functional Analysis · Mathematics 2007-05-23 Ravi Montenegro

Motivated by the celebrated Beck-Fiala conjecture, we consider the random setting where there are $n$ elements and $m$ sets and each element lies in $t$ randomly chosen sets. In this setting, Ezra and Lovett showed an $O((t \log t)^{1/2})$…

Data Structures and Algorithms · Computer Science 2018-10-09 Nikhil Bansal , Raghu Meka

We achieve new results on skew polynomial rings and their quotients, including the first explicit example of a skew polynomial ring where the ratio of the degree of a skew polynomial to the degree of its bound is not extremal. These methods…

Combinatorics · Mathematics 2025-02-20 F. J. Lobillo , Paolo Santonastaso , John Sheekey

Let $(M^n,g)$ be a complete simply connected $n$-dimensional Riemannian manifold with curvature bounds $\operatorname{Sect}_g\leq \kappa$ for $\kappa\leq 0$ and $\operatorname{Ric}_g\geq(n-1)Kg$ for $K\leq 0$. We prove that for any bounded…

Differential Geometry · Mathematics 2020-03-09 Xiaolong Li , Kui Wang , Haotian Wu

We study density thresholds that force a measurable set $E\subseteq\mathbb{R}^d$ to contain all sufficiently large similar copies of every $n$-point configuration. We prove a lower bound of the form $1-O((\log n)/n)$, which matches the…

Classical Analysis and ODEs · Mathematics 2026-04-21 Vjekoslav Kovač , Adian Anibal Santos Sepčić

Recent breakthroughs in quantum query complexity have shown that any formula of size n can be evaluated with O(sqrt(n)log(n)/log log(n)) many quantum queries in the bounded-error setting [FGG08, ACRSZ07, RS08b, Rei09]. In particular, this…

Computational Complexity · Computer Science 2009-09-28 Troy Lee

We investigate the maximal size of an increasing subset among points randomly sampled from certain probability densities. Kerov and Vershik's celebrated result states that the largest increasing subset among $N$ uniformly random points on…

Probability · Mathematics 2024-12-19 Victor Dubach

Eberhard and Pohoata conjectured that every $3$-cube-free subset of $[N]$ has size less than $2N/3+o(N)$. In this paper we show that if we replace $[N]$ with $\mathbb{Z}_N$ the upper bound of $2N/3$ holds, and the bound is tight when $N$ is…

Combinatorics · Mathematics 2025-04-04 Yuchen Meng

For positive integers $n$ and $m$, consider a multiset of non-empty subsets of $[m]$ such that there is a \textit{unique} partition of these subsets into $n$ partitions of $[m]$. We study the maximum possible size $g(n,m)$ of such a…

Combinatorics · Mathematics 2022-09-02 Varun Sivashankar

Given a finite set satisfying condition $\mathcal{A}$, the subset selection problem asks, how large of a subset satisfying condition $\mathcal{B}$ can we find? We make progress on three instances of subset selection problems in planar point…

Combinatorics · Mathematics 2024-12-20 József Balogh , Felix Christian Clemen , Adrian Dumitrescu , Dingyuan Liu

In a recent paper Petrov and Pohoata developed a new algebraic method which combines the Croot-Lev-Pach Lemma from additive combinatorics and Sylvester's Law of Inertia for real quadratic forms. As an application, they gave a simple proof…

Combinatorics · Mathematics 2020-07-02 Gábor Hegedüs , Lajos Rónyai