Expertini Research Research

Browse Research Papers

1,728+ open-access research outputs.

โœ• Clear
๐Ÿ” daniel karch ๐Ÿ“‚ Mathematics
Showing 1728 results for "daniel karch" in Mathematics
Mathematics Preprint PDF DOI

Recovering Product BMO from Schatten Hankel operators

Konstantinos Bampouras, Karl-Mikael Perfekt ยท 2026

We prove that if a small Hankel operator on the product Hardy space belongs to some Schatten class $S^p$, $p < \infty$, then it has a symbol in product BMO. In other words, the conclusion of Nehari's โ€ฆ

Read Paper โ†’
Mathematics Preprint PDF DOI

Quasi-Monte Carlo with a Hankel random digital net

Takashi Goda, Yang Liu, Raul Tempone ยท 2026

This paper proposes a new randomized design of digital nets in which the generating matrices are chosen to be random Hankel matrices. Compared with previous randomized designs of digital nets, this apโ€ฆ

Read Paper โ†’
Mathematics Preprint PDF DOI

A Milestone in Formalization: The Sphere Packing Problem in Dimension 8

Sidharth Hariharan, Christopher Birkbeck, Seewoo Lee, Ho Kiu Gareth Ma, Bhavik Mehta, Auguste Poiroux, Maryna Viazovska ยท 2026

In 2016, Viazovska famously solved the sphere packing problem in dimension $8$, using modular forms to construct a 'magic' function satisfying optimality conditions determined by Cohn and Elkies in 20โ€ฆ

Read Paper โ†’
Mathematics Preprint PDF DOI

On the Third Hankel Determinant for Inverse Coefficients of Starlike Functions: A Bernstein Polynomial Approach

Vasudevarao Allu, Shobhit Kumar ยท 2026

Let $\mathcal{A}$ denote the class of normalized analytic functions $f$ in the open unit disk defined as $ \mathbb{D}:=\{z\in\mathbb{C}:|z|<1\} $ with $f(0)=0$ and $f'(0)=1$. A function $f\in\โ€ฆ

Read Paper โ†’
Mathematics Preprint PDF DOI

Mesh-Intrinsic GFEM: High-Order Smoothness on $C^0$ Unstructured Meshes

Rong Tian ยท 2026

High-order partial differential equations (PDEs) require derivative regularity that standard $C^0$ finite element infrastructures do not directly provide on unstructured meshes. We propose a mesh-intrโ€ฆ

Read Paper โ†’
Mathematics Preprint PDF DOI

On the rank of quaternion Hankel matrices

Philippe Flores, Julien Flamant, Nicolas Le Bihan ยท 2026

This paper discusses the left and right ranks of quaternion matrices with Hankel structure. While they are in general different for arbitrary quaternion matrices, we show that the left and right ranksโ€ฆ

Read Paper โ†’
Mathematics Preprint PDF DOI

Measles Resurgence in Bangladesh, 2026: A Situational Analysis for Urgent Public Health Response

Md. Kamrujjaman, Faizunnesa Khondaker, Alvi Ahmed Sarker, Nuzhat Nuari Khan Rivu ยท 2026

\textbf{Background} Measles has resurged globally in the post-pandemic period as routine immunisation recovery remains below the two-dose threshold required to interrupt transmission. Bangladesh, prevโ€ฆ

Read Paper โ†’
Mathematics Preprint PDF DOI

Sharp Estimates of Hankel Determinants for certain classes of convex univalent functions

Vasudevarao Allu, Shobhit Kumar ยท 2026

Let $\mathcal{A}$ denote the class of analytic functions $f$ such that $f(0)=0$ and $f'(0)=1$ in the unit disk $\mathbb{D}:=\{z \in \mathbb{C}: |z|<1\}.$ We examine the properties of the class $\mathcโ€ฆ

Read Paper โ†’
Mathematics Preprint PDF DOI

A DPG method for the circular arch problem

Norbert Heuer, Antti H. Niemi ยท 2026

We consider an elastic model for a circular arch that incorporates membrane, transverse shear, and bending effects. The central line of the arch is partitioned into elements, and an ultra-weak variatiโ€ฆ

Read Paper โ†’
Mathematics Preprint PDF DOI

The second and third Hankel determinants for certain convex subclass of functions

Vasudevarao Allu, Shobhit Kumar ยท 2026

Let $\mathcal{A}$ denote the class of analytic functions such that $f(0)=0$ and $f'(0)=1$ in the unit disk $\mathbb{D}:=\{z \in \mathbb{C}: |z|<1\}.$ In the present paper, we consider $\mathcal{C}(\vaโ€ฆ

Read Paper โ†’
Mathematics Preprint PDF DOI

The second and third Hankel determinants for certain classes of functions

Vasudevarao Allu, Shobhit Kumar ยท 2026

Let $\mathcal{A}$ denote the class of analytic functions such that $f(0)=0$ and $f'(0)=1$ in the unit disk $\mathbb{D}:=\{z \in \mathbb{C}: |z|<1\}.$ In this paper, we consider $\mathcal{S}^*(\varphi)โ€ฆ

Read Paper โ†’
Mathematics Preprint PDF DOI

The second and third Hankel determinants for starlike MA--Minda subclass associated to quadratic polynomials

Vasudevarao Allu, Shobhit Kumar ยท 2026

Let $\mathcal{A}$ denote the class of analytic functions such that $f(0)=0$ and $f'(0)=1$ in the unit disk $\mathbb{D}:=\{z \in \mathbb{C}: |z|<1\}$. In this paper, we discuss the properties of a starโ€ฆ

Read Paper โ†’
Mathematics Preprint PDF DOI

Error terms for continued fractions of $e^{1/s}$ and $\sqrt{\frac{v}{u}}\tanh\!\Bigl(\frac{1}{\sqrt{uv}}\Bigr)$

Nikita Kalinin, Takao Komatsu ยท 2026

Many classical identities arise from nothing more mysterious than looking at the same object in two different ways. A number, a function, or a combinatorial object may admit several natural decompositโ€ฆ

Read Paper โ†’
Mathematics Preprint PDF DOI

Finite-time contact in fluid-elastic structure interaction: Navier-slip coupling condition

Krutika Tawri, Nash Ward ยท 2026

We consider a fluid-structure interaction problem involving a viscous, incompressible fluid flow, modeled by the 2D Navier-Stokes equations, through a thin deformable elastic tube, displacement of whiโ€ฆ

Read Paper โ†’
Mathematics Preprint PDF DOI

On a perturbed Hofstadter $Q$-recursion

Benoit Cloitre ยท 2026

The Hofstadter Q-sequence is a prominent example of nested recurrence. Despite decades of study, it is not even known whether Q(n) is defined for all n. Mantovanelli introduced a parity-perturbed variโ€ฆ

Read Paper โ†’
Mathematics Preprint PDF DOI

On a Conjecture about Sums Involving Farey Fractions

Anji Dong, Xinyi Li, Vi Anh Nguyen ยท 2026

In this paper, we prove a conjecture by Daniele Mundici on the sum of squared distances between consecutive elements in the $Q$-th Farey sequence for $Q\in\mathbb{Z}$ and $Q\geq 2$.โ€ฆ

Read Paper โ†’
Mathematics Preprint PDF DOI

On expectations and variances in the hard-core model

Weiyuan Zhang, Kexiang Xu ยท 2026

The hard-core model can be used to understand the numbers of independent sets in graphs in extremal graph theory. The occupancy fraction, defined as the logarithmic derivative of the independence polyโ€ฆ

Read Paper โ†’
Mathematics Preprint PDF DOI

The Grothendieck Constant is Strictly Larger than Davie-Reeds' Bound

Chris Jones, Giulio Malavolta ยท 2026

The Grothendieck constant $K_{G}$ is a fundamental quantity in functional analysis, with important connections to quantum information, combinatorial optimization, and the geometry of Banach spaces. Deโ€ฆ

Read Paper โ†’
Mathematics Preprint PDF DOI

90+ years of the Scottish Book

Stanis{l}aw Domoradzki, Ma{l}gorzata Stawiska, Mykhailo Zarichnyi ยท 2026

Inspired by the recent 90th anniversary of the Scottish Book we present some reflections about its impact. First we discuss new areas of mathematics it helped launch. Then we argue that it was activelโ€ฆ

Read Paper โ†’
Mathematics Preprint PDF DOI

Van der Waerden's theorem on arithmetic progressions -- a survey of some historical and modern developments

Vitaly Bergelson, Florian K. Richter ยท 2026

Van der Waerden's theorem, published in Nieuw. Arch. Wisk. 15 (1927), acted as a catalyst for major further developments in Ramsey theory. In this survey, we delve into the legacy of this mathematicalโ€ฆ

Read Paper โ†’
Page 1 of 87 Next โ†’