Results 71 to 80 of about 73,517 (203)

Hypergraphs with arbitrarily small codegree Turán density

open access: yesBulletin of the London Mathematical Society, Volume 58, Issue 4, April 2026.
Abstract The codegree Turán density γ(F)$\gamma (F)$ of a k$k$‐graph F$F$ is the smallest γ∈[0,1)$\gamma \in [0,1)$ such that every k$k$‐graph H$H$ with δk−1(H)⩾(γ+o(1))|V(H)|$\delta _{k-1}(H)\geqslant (\gamma +o(1))\vert V(H)\vert$ contains a copy of F$F$. In this work, we show that for every ε>0$\varepsilon >0$, there is a k$k$‐uniform hypergraph F$F$
Simón Piga, Bjarne Schülke
wiley   +1 more source

Noncommutative polygonal cluster algebras

open access: yesJournal of the London Mathematical Society, Volume 113, Issue 4, April 2026.
Abstract We define a new family of noncommutative generalizations of cluster algebras called polygonal cluster algebras. These algebras generalize the noncommutative surfaces of Berenstein–Retakh, and are inspired by the emerging theory of Θ$\Theta$‐positivity for the groups Spin(p,q)$\mathrm{Spin}(p,q)$.
Zachary Greenberg   +3 more
wiley   +1 more source

Some bounds related to the 2‐adic Littlewood conjecture

open access: yesMathematika, Volume 72, Issue 2, April 2026.
Abstract For every irrational real α$\alpha$, let M(α)=supn⩾1an(α)$M(\alpha) = \sup _{n\geqslant 1} a_n(\alpha)$ denote the largest partial quotient in its continued fraction expansion (or ∞$\infty$, if unbounded). The 2‐adic Littlewood conjecture (2LC) can be stated as follows: There exists no irrational α$\alpha$ such that M(2kα)$M(2^k \alpha)$ is ...
Dinis Vitorino, Ingrid Vukusic
wiley   +1 more source

Lebesgue's Density Theorem and definable selectors for ideals

open access: yes, 2019
We introduce a notion of density point and prove results analogous to Lebesgue's density theorem for various well-known ideals on Cantor space and Baire space. In fact, we isolate a class of ideals for which our results hold. In contrast to these results,
Müller, Sandra   +3 more
core   +1 more source

Non‐vanishing of Poincaré series on average

open access: yesMathematika, Volume 72, Issue 2, April 2026.
Abstract We study when Poincaré series for congruence subgroups do not vanish identically. We show that almost all Poincaré series with suitable parameters do not vanish when either the weight k$k$ or the index m$m$ varies in a dyadic interval. Crucially, analyzing the problem ‘on average’ over these weights or indices allows us to prove non‐vanishing ...
Ned Carmichael, Noam Kimmel
wiley   +1 more source

Traces of Hecke operators on Drinfeld modular forms for GL2(Fq[T])$\operatorname{GL}_2(\mathbb {F}_q[T])$

open access: yesMathematika, Volume 72, Issue 2, April 2026.
Abstract In this paper, we study traces of Hecke operators on Drinfeld modular forms of level 1 in the case A=Fq[T]$A = \mathbb {F}_q[T]$. We deduce closed‐form expressions for traces of Hecke operators corresponding to primes of degree at most 2 and provide algorithms for primes of higher degree.
Sjoerd de Vries
wiley   +1 more source

Simple juntas for shifted families

open access: yesDiscrete Analysis, 2020
**For the moment the link is to the submitted version of the article. It will be updated when the final version has been posted to arXiv.** Simple juntas for shifted families, Discrete Analysis 2020:14, 18 pp.
Peter Frankl, Andrey Kupavskii
doaj   +1 more source

Variants of a theorem of Macbeath in finite‐dimensional normed spaces

open access: yesMathematika, Volume 72, Issue 2, April 2026.
Abstract A classical theorem of Macbeath states that for any integers d⩾2$d \geqslant 2$, n⩾d+1$n \geqslant d+1$, d$d$‐dimensional Euclidean balls are hardest to approximate, in terms of volume difference, by inscribed convex polytopes with n$n$ vertices.
Zsolt Lángi, Shanshan Wang
wiley   +1 more source

Avoidability of formulas with two variables

open access: yes, 2016
In combinatorics on words, a word $w$ over an alphabet $\Sigma$ is said to avoid a pattern $p$ over an alphabet $\Delta$ of variables if there is no factor $f$ of $w$ such that $f=h(p)$ where $h:\Delta^*\to\Sigma^*$ is a non-erasing morphism.
A Thue   +7 more
core   +4 more sources

Ordinary primes for GL2$\operatorname{GL}_2$‐type abelian varieties and weight 2 modular forms

open access: yesMathematika, Volume 72, Issue 2, April 2026.
Abstract Let A$A$ be a g$g$‐dimensional abelian variety defined over a number field F$F$. It is conjectured that the set of ordinary primes of A$A$ over F$F$ has positive density, and this is known to be true when g=1,2$g=1, 2$, or for certain abelian varieties with extra endomorphisms.
Tian Wang, Pengcheng Zhang
wiley   +1 more source

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