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Related papers: Cutting 4 by $n$ grids into two congruent pieces

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Consider the set of points formed by the integer $n \times n$ grid, and the process that in each iteration removes from the point set the vertices of its convex-hull. Here, we prove that the number of iterations of this process is…

Discrete Mathematics · Computer Science 2016-12-16 Sariel Har-Peled , Bernard Lidický

This paper deals with the history of the following problem: "Can an arbitrary rectangle be dissected into 3 non-rectangular congruent regions?" We present a new elementary proof that the answer is indeed no.

Geometric modeling by constraints leads to large systems of algebraic equations. This paper studies bipartite graphs underlaid by systems of equations. It shows how these graphs make possible to polynomially decompose these systems into…

Discrete Mathematics · Computer Science 2014-05-26 Samy Ait-Aoudia , Roland Jegou , Dominique Michelucci

We introduce a computational origami problem which we call the segment folding problem: given a set of $n$ line-segments in the plane the aim is to make creases along all segments in the minimum number of folding steps. Note that a folding…

Computational Geometry · Computer Science 2022-01-17 Takashi Horiyama , Fabian Klute , Matias Korman , Irene Parada , Ryuhei Uehara , Katsuhisa Yamanaka

The famous pancake theorem states that for every finite set $X$ in the plane, there exist two orthogonal lines that divide $X$ into four equal parts. We propose an algorithm whose running time is linear in the number of points in $X$ and…

Combinatorics · Mathematics 2026-02-03 Alexey Fakhrutdinov , Oleg R. Musin

The famous Gallai's Conjecture states that any connected graph with n vertices has a path decomposition containing at most (n+1)/2 paths. In this note, we explore graphs generated from removing edges from complete graphs. We first provide…

Combinatorics · Mathematics 2022-11-01 Hua Wang , Andrew Zhang

Divide and Conquer is a well known algorithmic procedure for solving many kinds of problem. In this procedure, the problem is partitioned into two parts until the problem is trivially solvable. Finding the distance of the closest pair is an…

Computational Geometry · Computer Science 2011-11-11 Mohammad Zaidul Karim , Nargis Akter

In 1968, Gallai conjectured that the edges of any connected graph with $n$ vertices can be partitioned into $\lceil \frac{n}{2} \rceil$ paths. We show that this conjecture is true for every planar graph. More precisely, we show that every…

Combinatorics · Mathematics 2022-06-22 Alexandre Blanché , Marthe Bonamy , Nicolas Bonichon

A new algorithm is proposed to accelerate RANSAC model quality calculations. The method is based on partitioning the joint correspondence space, e.g., 2D-2D point correspondences, into a pair of regular grids. The grid cells are mapped by…

Computer Vision and Pattern Recognition · Computer Science 2022-07-21 Daniel Barath , Gabor Valasek

We solve Poisson's equation using new multigrid algorithms that converge rapidly. The novel feature of the 2D and 3D algorithms are the use of extra diagonal grids in the multigrid hierarchy for a much richer and effective communication…

Numerical Analysis · Mathematics 2025-10-20 A. J. Roberts

We study the disproportionate version of the classical cake-cutting problem: how efficiently can we divide a cake, here $[0,1]$, among $n$ agents with different demands $\alpha_1, \alpha_2, \dots, \alpha_n$ summing to $1$? When all the…

Combinatorics · Mathematics 2019-09-17 Logan Crew , Bhargav Narayanan , Sophie Spirkl

We introduce and study the Separation Problem for infinite graphs, which involves determining whether a connected graph splits into at least two infinite connected components after the removal of a given finite set of edges. We prove that…

Logic · Mathematics 2026-02-11 Nicanor Carrasco-Vargas , Valentino Delle Rose , Cristóbal Rojas

In this article we study the problem of fair division. In particular we study a notion introduced by J. Barbanel that generalizes super envy-free fair division. We give a new proof of his result. Our approach allows us to give an explicit…

Computer Science and Game Theory · Computer Science 2017-07-11 Guillaume Chèze , Luca Amodei

We present a new numerical approach that is able to solve the multi-dimensional radiative transfer equations in all opacity regimes on a Lagrangian, unstructured network of characteristics based on a stochastic point process. Our method…

Astrophysics · Physics 2007-05-23 Jelle Ritzerveld , Vincent Icke , Erik-Jan Rijkhorst

To numerically solve a generic elliptic equation on two-dimensional domains with rectangular Cartesian grids, we propose a cut-cell geometric multigrid method that features (1) general algorithmic steps that apply to two-dimensional…

Numerical Analysis · Mathematics 2026-01-19 Jiyu Liu , Zhixuan Li , Jiatu Yan , Zhiqi Li , Qinghai Zhang

Previous work showed that, for $\nu_2(n)$ the number of partitions of $n$ into exactly two part sizes, one has $\nu_2(16n + 14) \equiv 0 \pmod{4}$. The earlier proof required the technology of modular forms, and a combinatorial proof was…

Combinatorics · Mathematics 2025-07-21 Eli R. DeWitt , William J. Keith

What is the smallest number of pieces that you can cut an n-sided regular polygon into so that the pieces can be rearranged to form a rectangle? Call it r(n). The rectangle may have any proportions you wish, as long as it is a rectangle.…

Combinatorics · Mathematics 2023-09-27 N. J. A. Sloane , Gavin A. Theobald

Gallai's path decomposition conjecture states that the edges of any connected graph on n vertices can be decomposed into at most (n+1)/2 paths. We confirm that conjecture for all graphs with maximum degree at most five.

Combinatorics · Mathematics 2016-09-21 Marthe Bonamy , Thomas Perrett

We consider multi-layered cake cutting in order to fairly allocate numerous divisible resources (layers of cake) among a group of agents under two constraints: contiguity and feasibility. We first introduce a new computational model in a…

Artificial Intelligence · Computer Science 2024-03-19 Mohammad Azharuddin Sanpui

The circular median problem in the Double-Cut-and-Join (DCJ) distance asks to find, for three given genomes, a fourth circular genome that minimizes the sum of the mutual distances with the three other ones. This problem has been shown to…

Discrete Mathematics · Computer Science 2011-11-28 Ahmad Mahmoody-Ghaidary , Cedric Chauve , Ladislav Stacho