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We present a refinement of Ramsey numbers by considering graphs with a partial ordering on their vertices. This is a natural extension of the ordered Ramsey numbers. We formalize situations in which we can use arbitrary families of…

Combinatorics · Mathematics 2016-11-29 Christopher Cox , Derrick Stolee

Ramsey theory looks for regularities in large objects. Model theory studies algebraic structures as models of theories. The structural Ramsey theory combines these two fields and is concerned with Ramsey-type questions about certain…

Combinatorics · Mathematics 2018-05-22 Matěj Konečný

We consider how the problem of determining normal forms for a specific class of nonholonomic systems leads to various interesting and concrete bridges between two apparently unrelated themes. Various ideas that traditionally pertain to the…

Differential Geometry · Mathematics 2023-08-21 Alex L Castro , Wyatt Howard , Corey Shanbrom

The Tur\'an hypergraph problem asks to find the maximum number of $r$-edges in a $r$-uniform hypergraph on $n$ vertices that does not contain a clique of size $a$. When $r=2$, i.e., for graphs, the answer is well-known and can be found in…

Combinatorics · Mathematics 2016-10-14 Annie Raymond

Since its formulation, Tur\'an's hypergraph problems have been among the most challenging open problems in extremal combinatorics. One of them is the following: given a $3$-uniform hypergraph $\mathcal{F}$ on $n$ vertices in which any five…

Combinatorics · Mathematics 2020-04-24 Peter Frankl , Hao Huang , Vojtěch Rödl

Several papers have been written studying unexpected hypersurfaces. We say a finite set of points Z admits unexpected hypersurfaces if a general union of fat linear subspaces imposes less that the expected number of conditions on the ideal…

Algebraic Geometry · Mathematics 2020-03-06 Bill Trok

Let $b$ be a symmetric or alternating bilinear form on a finite-dimensional vector space $V$. When the characteristic of the underlying field is not $2$, we determine the greatest dimension for a linear subspace of nilpotent $b$-symmetric…

Rings and Algebras · Mathematics 2018-04-24 Clément de Seguins Pazzis

We give the first exact and stability results for a hypergraph Tur\'{a}n problem with infinitely many extremal constructions that are far from each other in edit-distance. This includes an example of triple systems with Tur\'{a}n density…

Combinatorics · Mathematics 2023-12-04 Jianfeng Hou , Heng Li , Xizhi Liu , Dhruv Mubayi , Yixiao Zhang

The \emph{Ramsey multiplicity constant} of a graph $H$ is the limit as $n$ tends to infinity of the minimum density of monochromatic labeled copies of $H$ in a $2$-edge colouring of $K_n$. Fox and Wigderson recently identified a large…

Combinatorics · Mathematics 2024-01-31 Joseph Hyde , Jae-baek Lee , Jonathan A. Noel

Extending an earlier conjecture of Erd\H{o}s, Burr and Rosta conjectured that among all two-colorings of the edges of a complete graph, the uniformly random coloring asymptotically minimizes the number of monochromatic copies of any fixed…

Combinatorics · Mathematics 2023-06-28 Jacob Fox , Yuval Wigderson

We give asymptotically optimal constructions in generalized Ramsey theory using results about conflict-free hypergraph matchings. For example, we present an edge-coloring of $K_{n,n}$ with $2n/3 + o(n)$ colors such that each $4$-cycle…

Combinatorics · Mathematics 2022-08-29 Felix Joos , Dhruv Mubayi

We study the local geometry of the space of horizontal curves with endpoints freely varying in two given submanifolds $\mathcal P$ and $\mathcal Q$ of a manifold $\mathcal M$ endowed with a distribution $\mathcal D\subset T\M$. We give a…

Differential Geometry · Mathematics 2007-05-23 Paolo Piccione , Daniel V. Tausk

We define analytic maps between super Riemann surfaces which extend the notion of branched covering maps to a supersymmetric setting. We show that these super covering maps appear naturally both in symmetric product orbifolds of…

High Energy Physics - Theory · Physics 2026-02-06 Beat Nairz

The invariants of the Thomas and the Weyl type for a mapping between non-symmetric affine connection spaces are obtained with respect to the factored deformation tensor in this paper. Motivated by two invariants of the Weyl type obtained in…

Differential Geometry · Mathematics 2020-03-26 Nenad O. Vesić

Although the introduction of generalised and extended geometry has been motivated mainly by the appearance of dualities upon reductions on tori, it has until now been unclear how (all) the duality transformations arise from first principles…

High Energy Physics - Theory · Physics 2015-06-22 Martin Cederwall

Alon, Balogh, Keevash and Sudakov proved that the $(k-1)$-partite Tur\'an graph maximizes the number of distinct $r$-edge-colorings with no monochromatic $K_k$ for all fixed $k$ and $r=2,3$, among all $n$-vertex graphs. In this paper, we…

Combinatorics · Mathematics 2017-04-25 József Balogh , Hong Liu , Maryam Sharifzadeh

Many problems in extremal combinatorics can be reduced to determining the independence number of a specific auxiliary hypergraph. We present two such problems, one from discrete geometry and one from hypergraph Tur\'an theory. Using results…

Combinatorics · Mathematics 2024-06-04 Felix Christian Clemen

This paper extends some results of Hatcher and Quinn beyond the metastable range. We give a bordism theoretic obstruction to deforming a map between manifolds simultaneously off of a collection of pairwise disjoint submanifolds under the…

Algebraic Topology · Mathematics 2019-05-29 John R. Klein , Bruce Williams

We give an overview of recent progress around a problem introduced by Elekes and R\'onyai. The prototype problem is to show that a polynomial $f\in \mathbb{R}[x,y]$ has a large image on a Cartesian product $A\times B\subset \mathbb{R}^2$,…

Combinatorics · Mathematics 2016-03-29 Frank de Zeeuw

The Tur\'{a}n problem asks for the largest number of edges ex$(n,H)$ in an $n$-vertex graph not containing a fixed forbidden subgraph $H$, which is one of the most important problems in extremal graph theory. However the order of magnitude…

Combinatorics · Mathematics 2024-08-06 Tao Zhang , Zixiang Xu , Gennian Ge