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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

We use a well known problem in discrete and computational geometry (partitions of measures by $k$-fans) as a motivation and as a point of departure to illustrate many aspects, both theoretical and computational, of the problem of…

Algebraic Topology · Mathematics 2007-05-23 Pavle V. M. Blagojevic , Sinisa T. Vrecica , Rade T. Zivaljevic

In this paper, we introduce the notion of an admissible partition of a simplicial polyhedral fan and define the category of a partitioned fan as a generalisation of the $\tau$-cluster morphism category of a finite-dimensional algebra. This…

Representation Theory · Mathematics 2025-02-26 Maximilian Kaipel

Given a homogenous Poisson point process in the plane, we prove that it is possible to partition the plane into bounded connected cells of equal volume, in a translation-invariant way, with each point of the process contained in exactly one…

Probability · Mathematics 2014-10-13 Alexander E. Holroyd , James B. Martin

Let d > 1 and 0 < k < d. The k-plane transform satisies some Lp to Lq dilation-invariant inequality. In this case the best constant and the extremizers are explicitly known. We give a quantitative form of the inequality with respect to…

Classical Analysis and ODEs · Mathematics 2014-11-19 Alexis Drouot

We generalize the ham sandwich theorem to $d+1$ measures in $\mathbb{R}^d$ as follows. Let $\mu_1,\mu_2, \dots, \mu_{d+1}$ be absolutely continuous finite Borel measures on $\mathbb{R}^d$. Let $\omega_i=\mu_i(\mathbb{R}^d)$ for $i\in…

Metric Geometry · Mathematics 2018-12-18 Mikio Kano , Jan Kynčl

Let $S$ be a finite set of geometric objects partitioned into classes or \emph{colors}. A subset $S'\subseteq S$ is said to be \emph{balanced} if $S'$ contains the same amount of elements of $S$ from each of the colors. We study several…

Computational Geometry · Computer Science 2017-08-22 Sergey Bereg , Matias Korman , Rodrigo I. Silveira , Ferran Hurtado , Dolores Lara , Jorge Urrutia , Mikio Kano , Carlos Seara , Kevin Verbeek

We show that, for any prime power n and any convex body K (i.e., a compact convex set with interior) in Rd, there exists a partition of K into n convex sets with equal volumes and equal surface areas. Similar results regarding…

Metric Geometry · Mathematics 2017-05-09 Roman Karasev , Alfredo Hubard , Boris Aronov

We prove the following theorem. Let $\mu$ be a measure on $R^n$ with even continuous density, and let $K,L$ be origin-symmetric convex bodies in $R^n$ so that $\mu(K\cap H)\le \mu(L\cap H)$ for any central hyperplane H. Then $\mu(K)\le…

Functional Analysis · Mathematics 2014-05-22 Alexander Koldobsky , Artem Zvavitch

A generalization of the Borsuk-Ulam theorem to Stiefel manifolds is considered. This theorem is applied to derive bounds on $d$ that guarantee-for a given set of $m$ measures in $\mathbb{R}^d$-the existence of $k$ mutually orthogonal…

Algebraic Topology · Mathematics 2026-05-26 Oleg R. Musin

We prove two results about transforming any convex polyhedron, modeled as a linkage L of its edges. First, if we subdivide each edge of L in half, then L can be continuously flattened into a plane. Second, if L is equilateral and we again…

Computational Geometry · Computer Science 2024-12-20 Erik D. Demaine , Martin L. Demaine , Markus Hecher , Rebecca Lin , Victor H. Luo , Chie Nara

A flag manifold over a semifield K can be partitioned into "half i-circles" which are orbits of a K-action on that flag manifold. Here i is fixed and it corresponds to a simple reflection in the Weyl group. We prove (for certain K) a…

Representation Theory · Mathematics 2022-12-21 G. Lusztig

Classic mass partition results are about dividing the plane into regions that are equal with respect to one or more measures (masses). We introduce a new concept in which the notion of partition is replaced by that of a cover. In this case…

We use recent extensions of the Borsuk--Ulam theorem for Stiefel manifolds to generalize the ham sandwich theorem to mass assignments. A $k$-dimensional mass assignment continuously imposes a measure on each $k$-dimensional affine subspace…

Combinatorics · Mathematics 2021-10-11 Ilani Axelrod-Freed , Pablo Soberón

Motivated by a question of R.\ Nandakumar, we show that the Euclidean plane can be dissected into mutually incongruent convex quadrangles of the same area and the same perimeter. As a byproduct we obtain vertex-to-vertex dissections of the…

Metric Geometry · Mathematics 2020-04-03 Dirk Frettlöh , Christian Richter

A family of $k$ point sets in $d$ dimensions is well-separated if the convex hulls of any two disjoint subfamilies can be separated by a hyperplane. Well-separation is a strong assumption that allows us to conclude that certain kinds of…

Computational Geometry · Computer Science 2022-09-07 Helena Bergold , Daniel Bertschinger , Nicolas Grelier , Wolfgang Mulzer , Patrick Schnider

It is proved that the number of partitions of n with odd mex and k parts that aren't ones equals the number of partitions of n with nonnegative crank and k parts that aren't ones..

Combinatorics · Mathematics 2025-08-26 George E Andrews , Moshe Newman

Let p(n, k) denote the number of partitions of n into parts less than or equal to k. We show several properties of this function modulo 2. First, we prove that for fixed positive integers k and m, p(n,k) is periodic modulo m. Using this, we…

Combinatorics · Mathematics 2018-11-21 Kedar Karhadkar

We prove that for every integer $k$, every finite set of points in the plane can be $k$-colored so that every half-plane that contains at least $2k-1$ points, also contains at least one point from every color class. We also show that the…

Combinatorics · Mathematics 2015-05-19 Shakhar Smorodinsky , Yelena Yuditsky

A "ham sandwich" theorem is established for n quaternionic Borel measures on quaternionic space H^n. For each finite subgroup G of S^3, it is shown that there is a quaternionic hyperplane H and a corresponding tiling of H^n into |G|…

Combinatorics · Mathematics 2011-09-06 Steven Simon