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We present an approach (the biroot method) for nth root approximation that yields closed-form rational functions with coefficients derived from binomial structures, Gaussian functions, or qualifying DAG structures. The method emerges from…

Combinatorics · Mathematics 2025-11-18 Isaac Wolford

The long-standing topological Tverberg conjecture claimed, for any continuous map from the boundary of an $N(q,d):=(q-1)(d+1)$-simplex to $d$-dimensional Euclidian space, the existence of $q$ pairwise disjoint subfaces whose images have…

Combinatorics · Mathematics 2018-08-23 Steven Simon

We show that if the ground set of a matroid can be partitioned into $k\ge 2$ bases, then for any given subset $S$ of the ground set, there is a partition into $k$ bases such that the sizes of the intersections of the bases with $S$ may…

Combinatorics · Mathematics 2025-12-02 Hannaneh Akrami , Siyue Liu , Roshan Raj , László A. Végh

Huang, McKinnon, and Satriano conjectured that if $v \in \mathbb{R}^n$ has distinct coordinates and $n \geq 3$, then a hyperplane through the origin other than $\sum_i x_i = 0$ contains at most $2\lfloor n/2 \rfloor (n-2)!$ of the vectors…

Combinatorics · Mathematics 2020-02-21 Brendan Pawlowski

A fundamental theorem of linear algebra asserts that every basis for the vector space $\mathbb{R}^n$ has $n$ elements. In this expository note we present a theorem of W. G. Leavitt describing one way in which this invariant basis number…

Rings and Algebras · Mathematics 2022-03-25 Tyrone Crisp

We prove a logical implication between two old conjectures stated by Bapat and Sunder about the permanent of positive semidefinite matrices. Although Drury has recently disproved both conjectures, this logical implication yields a…

Rings and Algebras · Mathematics 2025-08-04 Léo Pioge , Kamil K. Pietrasz , Benoit Seron , Leonardo Novo , Nicolas J. Cerf

The bounded orbit conjecture says that every homeomorphism on the plane with each of its orbits being bounded must have a fixed point. Brouwer's translation theorem asserts that the conjecture is true for orientation preserving…

Dynamical Systems · Mathematics 2025-04-11 Jiehua Mai , Enhui Shi , Kesong Yan , Fanping Zeng

A transversal matroid whose dual is also transversal is called bi-transversal. Let $G$ be an undirected graph with vertex set $V$. In this paper, for every subset $W$ of $V$, we associate a bi-transversal matroid to the pair $(G,W)$. We…

Combinatorics · Mathematics 2024-03-01 Mahdi Ebrahimi

We show that any finite dimensional von Neumann algebra admits an orthonormal unitary basis with respect to its standard trace. We also show that a finite dimensional von Neumann subalgebra of $M_n(\mathbb{C})$ admits an orthonormal unitary…

Operator Algebras · Mathematics 2022-11-22 Jason Crann , David W. Kribs , Rajesh Pereira

Say that mu is a ``subpartition'' of an integer partition lambda if the multiset of parts of mu is a submultiset of the parts of lambda, and define an integer partition lambda to be ``wide'' if for every subpartition mu of lambda, mu >= mu'…

Combinatorics · Mathematics 2007-05-23 Timothy Y. Chow , C. Kenneth Fan , Michel X. Goemans , Jan Vondrak

Let $(P,\leq)$ be a finite poset (partially ordered set), where $P$ has cardinality $n$. Consider linear extensions of $P$ as permutations $x_1x_2\cdots x_n$ in one-line notation. For distinct elements $x,y\in P$, we define…

Combinatorics · Mathematics 2018-02-02 Emily J. Olson , Bruce E. Sagan

The Erd\H{o}s-Szekeres conjecture states that any set of more than $2^{n-2}$ points in the plane with no three on a line contains the vertices of a convex $n$-gon. Erd\H{o}s, Tuza, and Valtr strengthened the conjecture by stating that any…

Combinatorics · Mathematics 2022-10-11 Jineon Baek

Let $G$ be a connected multigraph with $n$ vertices, and suppose $G$ has been edge-colored with $n-1$ colors so that each color class induces a spanning tree. Rota's Basis Conjecture for graphic matroids posits that one can find $n-1$…

Combinatorics · Mathematics 2023-11-02 Anant Asthana , Shreev Goyal

The existence problem for mutually unbiased bases is an unsolved problem in quantum information theory. A related question is whether every pair of bases admits vectors that are unbiased to both. Mathematically this translates to the…

Quantum Physics · Physics 2017-01-18 Ole Andersson , Ingemar Bengtsson

For a matroid $M$ of rank $r$ on $n$ elements, let $b(M)$ denote the fraction of bases of $M$ among the subsets of the ground set with cardinality $r$. We show that $$\Omega(1/n)\leq 1-b(M)\leq O(\log(n)^3/n)\text{ as }n\rightarrow \infty$$…

Combinatorics · Mathematics 2016-10-24 Rudi Pendavingh , Jorn van der Pol

In this paper, we prove that there exist at least $n$ geometrically distinct brake orbits on every $C^2$ compact convex symmetric hypersurface $\Sg$ in $\R^{2n}$ satisfying the reversible condition $N\Sg=\Sg$ with $N=\diag (-I_n,I_n)$. As a…

Dynamical Systems · Mathematics 2016-12-14 Chungen Liu , Duanzhi Zhang

In $1980$ White conjectured that every element of the toric ideal of a matroid is generated by quadratic binomials corresponding to symmetric exchanges. We prove White's conjecture for high degrees with respect to the rank. This extends our…

Combinatorics · Mathematics 2021-12-01 Michał Lasoń

The $1/3$-$2/3$ Conjecture, originally formulated in 1968, is one of the best-known open problems in the theory of posets, stating that the balance constant (a quantity determined by the linear extensions) of any non-total order is at least…

Combinatorics · Mathematics 2024-09-17 Christian Gaetz , Yibo Gao

In 1999 Merino and Welsh conjectured that evaluations of the Tutte polynomial of a graph satisfy an inequality. In this short article we show that the conjecture generalized to matroids holds for the large class of all split matroids by…

Combinatorics · Mathematics 2023-09-11 Luis Ferroni , Benjamin Schröter

For $n \geq 2$ we construct a measurable subset of the unit ball in $\mathbb{R}^n$ that does not contain pairs of points at distance 1 and whose volume is greater than $(1/2)^n$ times the volume of the ball. This disproves a conjecture of…

Metric Geometry · Mathematics 2019-05-15 Fernando Mário de Oliveira Filho , Frank Vallentin