English
Related papers

Related papers: The Cameron-Liebler problem for sets

200 papers

We give a canonical partition of shifted intersecting set systems, from which one can obtain unified and elementary proofs of the Erd\H{o}s-Ko-Rado and Hilton-Milner Theorem, as well as a characterization of maximal shifted $k$-uniform…

Combinatorics · Mathematics 2022-06-28 Nguyen Trong Tuan , Nguyen Anh Thi

We present a systematic study of symmetries, invariants and moduli spaces of classes of coframes. We introduce a classifying Lie algebroid to give a complete description of the solution to Cartan's realization problem that applies to both…

Differential Geometry · Mathematics 2012-10-08 Rui Loja Fernandes , Ivan Struchiner

We classify the Boolean degree $1$ functions of $k$-spaces in a vector space of dimension $n$ (also known as Cameron-Liebler classes) over the field with $q$ elements for $n \geq n_0(k, q)$. This also implies that two-intersecting sets with…

Combinatorics · Mathematics 2024-05-28 Ferdinand Ihringer

Two perfect matchings $P$ and $Q$ of the complete graph on $2k$ vertices are said to be set-wise $t$-intersecting if there exist edges $P_{1}, \cdots, P_{t}$ in $P$ and $Q_{1}, \cdots, Q_{t}$ in $Q$ such that the union of edges $P_{1},…

Combinatorics · Mathematics 2021-10-06 Mahsa N. Shirazi

In this paper we prove an Erd\H{o}s-Ko-Rado-type theorem for intersecting sets of permutations. We show that an intersecting set of maximal size in the projective general linear group PGL(3,q), in its natural action on the points of the…

Combinatorics · Mathematics 2013-10-10 Karen Meagher , Pablo Spiga

Let $ACG(2\nu,\mathbb{F}_q)$ be the $2\nu$-dimensional classical affine space with parameter $e$ over a $q$-element finite field $\mathbb{F}_q$, and ${\cal O}_{\nu}$ be the set of all maximal totally isotropic flats in…

Combinatorics · Mathematics 2024-02-21 Jun Guo , Lingyu Wan

Cameron-Liebler sets of generators in polar spaces were introduced a few years ago as natural generalisations of the Cameron-Liebler sets of subspaces in projective spaces. In this article we present the first two constructions of…

Combinatorics · Mathematics 2023-10-24 Maarten De Boeck , Jozefien D'haeseleer , Morgan Rodgers

By using a combination of algebraic, geometric, and dynamical techniques, together with input from higher dimensional Diophantine approximation, we give a complete characterization of all linearly repetitive cut and project sets with…

Dynamical Systems · Mathematics 2017-02-15 Alan Haynes , Henna Koivusalo , James Walton

This paper introduces a problem of coherent-classical estimation for a class of linear quantum systems. In this problem, the estimator is a mixed quantum-classical system which produces a classical estimate of a system variable. The…

Quantum Physics · Physics 2013-10-23 Ian R. Petersen

There are 6 families of finite polar spaces of rank $3$. The set of lines in a rank $3$ polar space form a rank $5$ association scheme. We determine the regular sets of minimal size in several of these polar spaces, and describe some…

Combinatorics · Mathematics 2024-06-17 Ferdinand Ihringer , Morgan Rodgers

This paper studies "pro-excision" for the K-theory of one-dimensional (usually semi-local) rings and its various applications. In particular, we prove Geller's conjecture for equal characteristic rings over a perfect field of finite…

K-Theory and Homology · Mathematics 2013-09-03 Matthew Morrow

We show that the Skolem Problem is decidable in finitely generated commutative rings of positive characteristic. More precisely, we show that there exists an algorithm which, given a finite presentation of a (unitary) commutative ring…

Logic in Computer Science · Computer Science 2026-03-12 Ruiwen Dong , Doron Shafrir

In this article we use techniques developed by Hrushovski-Loeser to study certain metric properties of the Berkovich analytification of a finite morphism of smooth connected projective curves. In recent work, M. Temkin proved a radiality…

Algebraic Geometry · Mathematics 2018-01-03 John Welliaveetil

We define and investigate separable K-linear categories. We show that such a category C is locally finite and that every left C-module is projective. We apply our main results to characterize separable linear categories that are spanned by…

Quantum Algebra · Mathematics 2009-11-30 Andrei Chites , Costel Chites

We obtain relations among the characteristic classes of a manifold M admitting corank one maps. Our relations yield strong restrictions on the cobordism class of M and also nonexistence results for singular maps of the projective spaces. We…

Geometric Topology · Mathematics 2012-03-08 Boldizsar Kalmar , Tamas Terpai

In this paper, in the first we give definitions of some classes of division rings which strictly contain the class of centrally finite division rings. One of our main purpose is to construct non-trivial examples of rings of new defined…

Rings and Algebras · Mathematics 2011-03-16 Bui Xuan Hai , Mai Hoang Bien , Trinh Thanh Deo

We introduce characteristic classes for the spectral sequence associated to a split short exact sequence of Hopf algebras. We show that these characteristic classes can be seen as obstructions for the vanishing of differentials in the…

Algebraic Topology · Mathematics 2011-03-10 Dieter Degrijse , Nansen Petrosyan

The Erd\H{o}s--Ko--Rado theorem is extended to designs in semilattices with certain conditions. As an application, we show the intersection theorems for the Hamming schemes, the Johnson schemes, bilinear forms schemes, Grassmann schemes,…

Combinatorics · Mathematics 2012-01-25 Sho Suda

We extend the classical Landesman-Lazer results to the setting of second order Hamilton-Jacobi-Bellman equations. A number of new phenomena appear.

Analysis of PDEs · Mathematics 2010-10-27 Patricio Felmer , Alexander Quaas , Boyan Sirakov

In this short note we show that both generalizations of celebrated Erd\H{o}s--Ko--Rado theorem and Hilton--Milner theorem to the setting of exterior algebra in the simplest non-trivial case of two-forms follow from the folklore puzzle about…

Combinatorics · Mathematics 2022-01-27 Grigory Ivanov , Seyda Köse