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We bound the number of permutations with a fixed number $r$ of $321 \ominus p_0$ patterns by a constant times the number of permutations which avoid $321 \ominus p_0$. We use this new upper bound to show that the ordinary generating…

Combinatorics · Mathematics 2025-10-29 Michael Waite

Building on recent work of Mattheus and Verstra\"ete, we establish a general connection between Ramsey numbers of the form $r(F,t)$ for $F$ a fixed graph and a variant of the Zarankiewicz problem asking for the maximum number of 1s in an…

Combinatorics · Mathematics 2024-04-25 David Conlon , Sam Mattheus , Dhruv Mubayi , Jacques Verstraëte

The permanent of a multidimensional matrix is the sum of products of entries over all diagonals. By Minc's conjecture, there exists a reachable upper bound on the permanent of 2-dimensional (0,1)-matrices. In this paper we obtain some…

Combinatorics · Mathematics 2015-03-31 A. A. Taranenko

We establish an operator formula for the number of monotone trapezoids with prescribed bottom row, generalizing alternating sign matrices. The special case of the formula for monotone triangles previously provided an alternative proof for…

Combinatorics · Mathematics 2025-02-14 Ilse Fischer , Hans Höngesberg

Keszegh (2009) proved that the extremal function $ex(n, P)$ of any forbidden light $2$-dimensional 0-1 matrix $P$ is at most quasilinear in $n$, using a reduction to generalized Davenport-Schinzel sequences. We extend this result to…

Combinatorics · Mathematics 2018-05-16 Jesse Geneson

The paper is devoted to multidimensional $(0,1)$-matrices extremal with respect to containing a polydiagonal (a fractional generalization of a diagonal). Every extremal matrix is a threshold matrix, i.e., an entry belongs to its support…

Combinatorics · Mathematics 2023-11-17 Anna A. Taranenko

Let $M$ be a non-zero binary matrix with distinct rows where the rows are closed under certain logical operators. In this article, we investigate the existence of columns containing an equal or greater number of ones than zeros.…

Combinatorics · Mathematics 2023-09-12 Mohammad Javad Moghaddas Mehr

Let $ex(n, P)$ be the maximum possible number of ones in any 0-1 matrix of dimensions $n \times n$ that avoids $P$. Matrix $P$ is called minimally non-linear if $ex(n, P) = \omega(n)$ but $ex(n, P') = O(n)$ for every strict subpattern $P'$…

Discrete Mathematics · Computer Science 2017-01-04 P. A. CrowdMath

We study a special kind of bounds (so called forbidden subgraph bounds, cf. Feige, Verbitsky '02) for parallel repetition of multi-prover games. First, we show that forbidden subgraph upper bounds for $r \ge 3$ provers imply the same bounds…

Discrete Mathematics · Computer Science 2016-04-21 Jan Hązła , Thomas Holenstein , Anup Rao

Consider real bivariate polynomials f and g, respectively having 3 and m monomial terms. We prove that for all m>=3, there are systems of the form (f,g) having exactly 2m-1 roots in the positive quadrant. Even examples with m=4 having 7…

Algebraic Geometry · Mathematics 2007-09-18 Joel Gomez , Andrew Niles , J. Maurice Rojas

We give an elementary proof of a generalization of Bourgain and Tzafriri's Restricted Invertibility Theorem, which says roughly that any matrix with columns of unit length and bounded operator norm has a large coordinate subspace on which…

Functional Analysis · Mathematics 2010-10-05 Daniel A. Spielman , Nikhil Srivastava

We prove that a nonsymmetric normal entry pattern of order $n$ ($n\ge 3$) has at most $n(n-3)/2+3$ distinct indeterminates and up to permutation similarity this number is attained by a unique pattern which is explicitly described.

Combinatorics · Mathematics 2015-06-12 Zejun Huang , Xingzhi Zhan

Let L be any number field or $\mathfrak{p}$-adic field and consider F:=(f_1,...,f_k) where f_i is in L[x_1,...,x_n]\{0} for all i and there are exactly m distinct exponent vectors appearing in f_1,...,f_k. We prove that F has no more than…

Number Theory · Mathematics 2007-05-23 J. Maurice Rojas

In this undergraduate thesis, we expand on the study of statistics on restricted growth functions avoiding patterns initiated by Campbell, et. al. Restricted growth functions are of interest because they are in bijection with set…

Combinatorics · Mathematics 2020-03-12 Robert Dorward

We solve the problem of characterizing the existence of a polynomial matrix of fixed degree when its eigenstructure (or part of it) and some of its rows (columns) are prescribed. More specifically, we present a solution to the row (column)…

Rings and Algebras · Mathematics 2024-02-07 A. Amparan , I. Baragaña , S. Marcaida , A. Roca

For each positive integer $t$ and each sufficiently large integer $r$, we show that the maximum number of elements of a simple, rank-$r$, $\mathbb C$-representable matroid with no $U_{2,t+3}$-minor is $t{r\choose 2}+r$. We derive this as a…

Combinatorics · Mathematics 2025-02-13 Jim Geelen , Peter Nelson , Zach Walsh

A (q,k,t)-design matrix is an m x n matrix whose pattern of zeros/non-zeros satisfies the following design-like condition: each row has at most q non-zeros, each column has at least k non-zeros and the supports of every two columns…

Combinatorics · Mathematics 2011-03-11 Boaz Barak , Zeev Dvir , Avi Wigderson , Amir Yehudayoff

The VC-dimension of a family P of n-permutations is the largest integer k such that the set of restrictions of the permutations in P on some k-tuple of positions is the set of all k! permutation patterns. Let r_k(n) be the maximum size of a…

Combinatorics · Mathematics 2013-01-25 Josef Cibulka , Jan Kyncl

For all positive integers $\ell$ and $r$, we determine the maximum number of elements of a simple rank-$r$ positroid without the rank-$2$ uniform matroid $U_{2,\ell+2}$ as a minor, and characterize the matroids with the maximum number of…

Combinatorics · Mathematics 2025-12-18 Jonathan Boretsky , Zach Walsh

A preferential arrangement of a set is a total ordering of the elements of that set with ties allowed. A barred preferential arrangement is one in which the tied blocks of elements are ordered not only amongst themselves but also with…

Combinatorics · Mathematics 2012-06-28 Connor Ahlbach , Jeremy Usatine , Nicholas Pippenger
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