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Let $W$ denote the $n$-dimensional affine space over the finite field $\mathbb F_q$. We prove here a Bollob\'as-type upper bound in the case of the set of affine subspaces. We give a construction of a pair of families of affine subspaces,…

Combinatorics · Mathematics 2015-12-04 Gábor Hegedüs

Let $\{(A_i,B_i)\}_{i=1}^{m}$ be a collection of pairs of sets with $|A_i|=a$ and $|B_i|=b$ for $1\leq i\leq m$. Suppose that $A_i\cap B_j=\emptyset$ if and only if $i=j$, then by the famous Bollob\'{a}s theorem, we have the size of this…

Combinatorics · Mathematics 2021-08-25 Wenjun Yu , Xiangliang Kong , Yuanxiao Xi , Xiande Zhang , Gennian Ge

We prove an upper bound of the form $2^{O(d^2 \mathrm{polylog}\,d)}$ on the number of affine (resp. linear) equivalence classes of, by increasing order of generality, 2-level d-polytopes, d-cones and d-configurations. This in particular…

Combinatorics · Mathematics 2018-06-18 Samuel Fiorini , Marco Macchia , Kanstantsin Pashkovich

We investigate the combinatorial structure of subspaces of the exterior algebra of a finite-dimensional real vector space, working in parallel with the extremal combinatorics of hypergraphs. Using initial monomials, projections of the…

Combinatorics · Mathematics 2021-11-22 Alex Scott , Elizabeth Wilmer

In 1965, Bollob\'as proved that for a Bollob\'as set-pair system $\{(A_i,B_i)\mid i\in[m]\}$, the maximum value of $\sum_{i=1}^m\binom{|A_i|+|B_i|}{A_i}^{-1}$ is $1$. Heged\"{u}s and Frankl recently extended the concept of Bollob\'as…

Combinatorics · Mathematics 2025-01-03 Erfei Yue

The Bollob\'as set pairs inequality is a fundamental result in extremal set theory with many applications. In this paper, for $n \geq k \geq t \geq 2$, we consider a collection of $k$ families $\mathcal{A}_i: 1 \leq i \leq k$ where…

Combinatorics · Mathematics 2020-06-09 Jason O'Neill , Jacques Verstraete

Bollob\'as-type theorem determines the maximum cardinality of a Bollob\'as system of sets. The original result has been extended to various mathematical structures beyond sets, including vector spaces and affine spaces. This paper…

Combinatorics · Mathematics 2024-08-13 Erfei Yue , Benjian Lv , Péter Sziklai , Kaishun Wang

Bollob\'{a}s and Scott [5] conjectured that every graph $G$ has a balanced bipartite spanning subgraph $H$ such that for each $v\in V(G)$, $d_H(v)\ge (d_G(v)-1)/2$. In this paper, we show that every graphic sequence has a realization for…

Combinatorics · Mathematics 2017-01-26 Yuliang Ji , Jie Ma , Juan Yan , Xingxing Yu

If K is an odd-dimensional flag closed manifold, flag generalized homology sphere or a more general flag weak pseudomanifold with sufficiently many vertices, then the maximal number of edges in K is achieved by the balanced join of cycles.…

Combinatorics · Mathematics 2013-03-25 Michal Adamaszek

In this paper we study those submonoids of $\mathbb{N}^d$ which a non-trivial pseudo-Frobenius set. In the affine case, we prove that they are the affine semigroups whose associated algebra over a field has maximal projective dimension…

Commutative Algebra · Mathematics 2019-03-27 J. I. García-García , I. Ojeda , J. C. Rosales , A. Vigneron-Tenorio

The theory of analytic function spaces in very general tubular domains over symmetric cones is a relatively new interesting research area. Tube domains are very general and very complicated domains. Recently several new results in this…

Complex Variables · Mathematics 2025-09-29 R. F. Shamoyan

Let W_n(p,q) denote the minimum number of edges in an n x n bipartite graph G on vertex sets X,Y that satisfies the following condition; one can add the edges between X and Y that do not belong to G one after the other so that whenever a…

Combinatorics · Mathematics 2014-01-22 Guy Moshkovitz , Asaf Shapira

Given an open subset U of a projective curve Y and a smooth family f:V-->U of curves, with semi-stable reduction over Y, we show that for a sub variation of Hodge structures of rank >2 the Arakelov inequality must be strict. For families of…

Algebraic Geometry · Mathematics 2011-02-19 Eckart Viehweg , Kang Zuo

We prove an optimal restriction theorem for an arbitrary homogeneous polynomial hypersurface (of degree at least 2) in R^3, with affine curvature introduced as mitigating factor.

Classical Analysis and ODEs · Mathematics 2011-08-23 A. Carbery , C. Kenig , S. Ziesler

We introduce the Density Formula for (topological) drawings of graphs in the plane or on the sphere, which relates the number of edges, vertices, crossings, and sizes of cells in the drawing. We demonstrate its capability by providing…

We introduce in this article a new method to estimate the minimum distance of codes from algebraic surfaces. This lower bound is generic, i.e. can be applied to any surface, and turns out to be ``liftable'' under finite morphisms, paving…

Algebraic Geometry · Mathematics 2020-06-09 Alain Couvreur , Philippe Lebacque , Marc Perret

We define the class of high dimensional graph manifolds. These are compact smooth manifolds supporting a decomposition into finitely many pieces, each of which is diffeomorphic to the product of a torus with a finite volume hyperbolic…

Differential Geometry · Mathematics 2016-03-22 Roberto Frigerio , Jean-Francois Lafont , Alessandro Sisto

We refine and advance the study of the local structure of idempotent finite algebras started in [A.Bulatov, The Graph of a Relational Structure and Constraint Satisfaction Problems, LICS, 2004]. We introduce a graph-like structure on an…

Logic in Computer Science · Computer Science 2016-01-28 Andrei A. Bulatov

In 1951, Bang posed the affine plank conjecture, which remains open: If a convex body in $\mathbb{R}^d$ is covered by planks, then the total relative width of the planks is at least one. We prove a lower bound of $2/(1+\sqrt{d})$ for this…

Metric Geometry · Mathematics 2026-02-25 Egor Bakaev , Amir Yehudayoff

We answer a question of Serre from the 1980s on rational points of bounded height on projective thin sets, in degree at least $4$. For degrees $2$ and $3$ we improve the known bounds in general. The focus is on thin sets of type II, namely…

Number Theory · Mathematics 2026-01-21 Tijs Buggenhout , Raf Cluckers , Per Salberger , Tim Santens , Floris Vermeulen
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