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The segment number of a planar graph $G$ is the smallest number of line segments needed for a planar straight-line drawing of $G$. Dujmovi\'c, Eppstein, Suderman, and Wood [CGTA'07] introduced this measure for the visual complexity of…

Computational Geometry · Computer Science 2022-07-18 Ina Goeßmann , Jonathan Klawitter , Boris Klemz , Felix Klesen , Stephen Kobourov , Myroslav Kryven , Alexander Wolff , Johannes Zink

In this work, we prove a $\tilde{\Omega}(\lg^{3/2} n )$ unconditional lower bound on the maximum of the query time and update time for dynamic data structures supporting reachability queries in $n$-node directed acyclic graphs under edge…

Data Structures and Algorithms · Computer Science 2023-04-19 Kasper Green Larsen , Huacheng Yu

Given a finite grid in $\mathbb{R}^2$, how many lines are needed to cover all but one point at least $k$ times? Problems of this nature have been studied for decades, with a general lower bound having been established by Ball and Serra. We…

Combinatorics · Mathematics 2023-05-02 Anurag Bishnoi , Simona Boyadzhiyska , Shagnik Das , Yvonne den Bakker

It is proved that the total length of any set of countably many rectifiable curves, whose union meets all straight lines that intersect the unit square U, is at least 2.00002. This is the first improvement on the lower bound of 2…

Computational Geometry · Computer Science 2014-04-11 Akitoshi Kawamura , Sonoko Moriyama , Yota Otachi , János Pach

Clemm and Trebat-Leder (2014) proved that the number of quadratic number fields with absolute discriminant bounded by $x$ over which there exist elliptic curves with good reduction everywhere and rational $j$-invariant is $\gg…

Number Theory · Mathematics 2023-02-15 Benjamin Matschke , Abhijit S. Mudigonda

A well-known theorem of de Bruijn and Erd\H{o}s states that any set of $n$ non-collinear points in the plane determines at least $n$ lines. Chen and Chv\'{a}tal asked whether an analogous statement holds within the framework of finite…

Combinatorics · Mathematics 2012-07-17 Ida Kantor , Balazs Patkos

We give improved lower bounds for binary $3$-query locally correctable codes (3-LCCs) $C \colon \{0,1\}^k \rightarrow \{0,1\}^n$. Specifically, we prove: (1) If $C$ is a linear design 3-LCC, then $n \geq 2^{(1 - o(1))\sqrt{k} }$. A design…

Computational Complexity · Computer Science 2024-10-29 Pravesh K. Kothari , Peter Manohar

We explore various techniques for counting the number of straight-edge crossing-free graphs that can be embedded on a planar point set. In particular, we derive a lower bound on the ratio of the number of such graphs with $m+1$ edges to the…

Combinatorics · Mathematics 2019-05-24 Siddharth Prasad

We prove that every graph $G$ for which $\omega(G) \geq 3/4(\Delta(G) + 1)$, has an independent set $I$ such that $\omega(G - I) < \omega(G)$. It follows that a minimum counterexample $G$ to Reed's conjecture satisfies $\omega(G) <…

Combinatorics · Mathematics 2010-03-16 Landon Rabern

The Burning Number Conjecture claims that for every connected graph $G$ of order $n,$ its burning number satisfies $b(G) \le \lceil \sqrt{n} \rceil.$ While the conjecture remains open, we prove that it is asymptotically true when the order…

Harry Buhrman et al gave an Omega(sqrt n) lower bound for monotone graph properties in the adjacency matrix query model. Their proof is based on the polynomial method. However for some properties stronger lower bounds exist. We give an…

Quantum Physics · Physics 2007-05-23 Christoph Durr , Mehdi Mhalla , Yaohui Lei

We give a fairly elementary and simple proof that shows that the number of incidences between $m$ points and $n$ lines in ${\mathbb R}^3$, so that no plane contains more than $s$ lines, is $$ O\left(m^{1/2}n^{3/4}+ m^{2/3}n^{1/3}s^{1/3} + m…

Combinatorics · Mathematics 2015-01-13 Micha Sharir , Noam Solomon

We show that for $m$ points and $n$ lines in the real plane, the number of distinct distances between the points and the lines is $\Omega(m^{1/5}n^{3/5})$, as long as $m^{1/2}\le n\le m^2$. We also prove that for any $m$ points in the…

Metric Geometry · Mathematics 2015-12-31 Micha Sharir , Shakhar Smorodinsky , Claudiu Valculescu , Frank de Zeeuw

Motivated by applications to matrix multiplication algorithms, Pratt asked (ITCS'24) how large a subset of $[n] \times [n]$ could be without containing a skew-corner: three points $(x,y), (x,y+h),(x+h,y')$ with $h \ne 0$. We prove any skew…

Combinatorics · Mathematics 2025-09-30 Michael Jaber , Shachar Lovett , Anthony Ostuni

The 1-2-3 Conjecture asks whether almost all graphs can be (edge-)labelled with $1,2,3$ so that no two adjacent vertices are incident to the same sum of labels. In the last decades, several aspects of this problem have been studied in…

Combinatorics · Mathematics 2021-02-17 Julien Bensmail , Hervé Hocquard , Dimitri Lajou , Éric Sopena

For sufficiently large $n$, we show that in every configuration of $n$ points chosen inside the unit square there exists a triangle of area less than $n^{-8/7-1/2000}$. This improves upon a result of Koml\'os, Pintz and Szemer\'edi from…

Combinatorics · Mathematics 2023-05-30 Alex Cohen , Cosmin Pohoata , Dmitrii Zakharov

An r-unform n-vertex hypergraph H is said to have the Manickam-Mikl\'os-Singhi (MMS) property if for every assignment of weights to its vertices with nonnegative sum, the number of edges whose total weight is nonnegative is at least the…

Combinatorics · Mathematics 2014-05-28 Hao Huang , Benny Sudakov

In this paper, we show that the number of points that can be placed in the grid $n\times n\times \cdots \times n~(d~times)=n^d$ for all $d\in \mathbb{N}$ with $d\geq 2$ so that no three points are collinear satisfies the lower bound…

Combinatorics · Mathematics 2026-04-14 Theophilus Agama

We prove the joints conjecture, showing that for any $N$ lines in ${\Bbb R}^3$, there are at most $O(N^{{3 \over 2}})$ points at which 3 lines intersect non-coplanarly. We also prove a conjecture of Bourgain showing that given $N^2$ lines…

Combinatorics · Mathematics 2008-12-08 Larry Guth , Nets Hawk Katz

We prove a lower bound of $\Omega(n^2/\log^2 n)$ on the size of any syntactically multilinear arithmetic circuit computing some explicit multilinear polynomial $f(x_1, \ldots, x_n)$. Our approach expands and improves upon a result of Raz,…

Computational Complexity · Computer Science 2017-11-03 Noga Alon , Mrinal Kumar , Ben Lee Volk