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๐Ÿ” xin xia ๐Ÿ“‚ Mathematics
Showing 87739 results for "xin xia" in Mathematics
Mathematics Preprint PDF DOI

Beyond first-order accuracy in continuous-forcing immersed boundary methods, and their well-conditioned projection-based solution

Diederik Beckers, H. Jane Bae, Andres Goza ยท 2026

We introduce a refined immersed boundary (IB) methodology that is better-than-first-order accurate in practice, while preserving key properties of "continuous-forcing" IB approaches that retain a singโ€ฆ

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Mathematics Preprint PDF DOI

The proportion of permutations fixing a $k$-set

Ben Green, Mehtaab Sawhney ยท 2026

Denote by $p(k)$ the limit, as $n \rightarrow \infty$, of the probability that a random permutation on a set of size $n$ has an invariant set of size $k$. We give an asymptotic formula for $p(k)$, shoโ€ฆ

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Mathematics Preprint PDF DOI

A torsion-intersection proof of perfect-cuboid nonexistence on 1,072 explicit master-tuple fibers

Rene Peschmann ยท 2026

Building on the genus-3 reduction $C_A : w^2 = \lambda^8 + A \lambda^4 + 1$ established in our companion paper (arXiv:2604.09328), we give an unconditional proof of the perfect-cuboid conjecture ("Conโ€ฆ

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Mathematics Preprint PDF DOI

Extremal graphs for average size of maximal matchings in bicyclic graphs

Kai Zhang ยท 2026

For a graph \(G\), let $avm(G)$ denote the average size of its maximal matchings. This parameter was introduced by Engbers and Erey in the study of extremal problems for maximal matchings, and they asโ€ฆ

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Mathematics Preprint PDF DOI

Minimal Parametric Networks in Hyperspaces and their Properties

Arsen Galstyan ยท 2026

This work investigates minimal parametric networks in hyperspaces of closed subsets of metric spaces endowed with the Hausdorff distance. It is shown that the problems of finding such networks are nonโ€ฆ

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Mathematics Preprint PDF DOI

Cliques in minimally globally rigid graphs

Julien Portier ยท 2026

We show that every minimally generically globally rigid graph in $\mathbb R^d$ which contains a subgraph isomorphic to $K_{d+2}$ is itself isomorphic to $K_{d+2}$, confirming a conjecture by Garamv{\"โ€ฆ

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Mathematics Preprint PDF DOI

Flexible GMRES converges in two phases

Stefan Guttel, Lauri Nyman ยท 2026

We derive a sharp upper bound on the residuals produced by the flexible GMRES (FGMRES) method. The bound shows that FGMRES exhibits two phases of convergence depending on the residual tolerance of theโ€ฆ

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Mathematics Preprint PDF DOI

Stationary Distribution of Brownian Motion in the Half-Plane with Two-sided Reflections

Jules Flin ยท 2026

We investigate the unique stationary measure of a positive recurrent reflecting Brownian motion in the upper half-plane, where the direction of reflection is constant on each half-axis. The Laplace trโ€ฆ

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Mathematics Preprint PDF DOI

Data-Driven Continuous-Time Linear Quadratic Regulator via Closed-Loop and Reinforcement Learning Parameterizations

Armin Gie{ss}ler, Felix Thommes, Soren Hohmann ยท 2026

This paper studies data-driven approaches to the continuous-time linear quadratic regulator (LQR) problem based on two existing parameterizations, namely a closed-loop (CL) parameterization from behavโ€ฆ

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Mathematics Preprint PDF DOI

Geometric densities and compression radii of knot types

Makoto Ozawa ยท 2026

We study scale-invariant geometric quantities associated with embedded closed curves in Euclidean three-space, with an emphasis on their behavior under optimization within a fixed knot type. Given a Eโ€ฆ

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Sufficient conditions for spanning $k$-trees in tough graphs

Caili Jia, Yong Lu ยท 2026

The toughness of a graph $G$, denoted by $\tau(G)$, is defined by $\tau(G)=$min $\{\frac{|S|}{c(G-S)}:S\subseteq V(G)$ and $c(G-S)\geq2\}$. A graph $G$ is said to be $\tau$-tough if $\tau(G)\geq \tau$โ€ฆ

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Time-dependent Robin heat equation via Markovian switching

Fausto Colantoni ยท 2026

This paper investigates the heat equation on a bounded domain with a Robin boundary condition, where the reactivity parameter (or killing rate) is modeled as a continuous-time Markov chain. We analyzeโ€ฆ

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Decoupled Descent: Exact Test Error Tracking Via Approximate Message Passing

Max Lovig ยท 2026

In modern parametric model training, full-batch gradient descent (and its variants) suffers due to progressively stronger biasing towards the exact realization of training data; this drives the systemโ€ฆ

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Irreducible Ferrers diagrams in the Etzion-Silberstein conjecture

Hugo Beeloo-Sauerbier Couvee, Alessandro Neri ยท 2026

The Etzion-Silberstein conjecture asserts that, for any finite field $\mathbb F$, Ferrers diagram $\mathcal D$, and integer $d$, there exists a linear matrix code supported on $\mathcal D$ with minimuโ€ฆ

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Mathematics Preprint PDF DOI

VC-Density in Divisible Oriented Abelian Groups and Their Pairs

Ebru Nayir, Melissa Ozsahakyan ยท 2026

We show that the VC-density in certain theories of oriented abelian groups is at most the size of parameter variables, which yields dp-minimality. We further prove that the VC-density of formulas in pโ€ฆ

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Separating Feasibility and Movement in Solution Discovery: The Case of Path Discovery

Hanno von Bergen, Larissa Fastenau, Enna Gerhard, Nicola Lorenz, Stephanie Maaz, Amer E. Mouawad, Roman Rabinovich, Nicole Schirrmacher, Daniel Schmand, Sebastian Siebertz, Mai Trinh ยท 2026

We study solution discovery, where the goal is to obtain a feasible solution to a problem from an initial configuration by a bounded sequence of local moves. In many applications, however, the graph tโ€ฆ

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Expected hyperbolic volumes of random beta polytopes

Zakhar Kabluchko, Philipp Schange ยท 2026

Let $X_1,\ldots,X_n$ be independent random points in the closed unit ball of $\mathbb{R}^d$. Assume that each $X_i$ has a beta distribution with parameter $\beta_i \ge -1$: if $\beta_i>-1$, then $X_i$โ€ฆ

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The existence criterion of holomorphic discs for higher $A_\infty$ operations via minimal discs

Qiang Tan, Zuyi Zhang ยท 2026

The main theorem of the paper provides an existence criterion of holomorphic discs for higher $A_\infty$ operations. The key step is to show that if a minimal disc in a K\"ahler manifold with boundaryโ€ฆ

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M\"obius-transformed trapezoidal rule for polynomial weights

Nuutti Hyvonen, Yuya Suzuki ยท 2026

This work studies numerical integration by the M\"obius-transformed trapezoidal rule, which combines the classical trapezoidal rule with a change of variables induced by a M\"obius transformation thatโ€ฆ

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G\r{a}rding Polynomials

Hao Fang, Biao Ma ยท 2026

We introduce G\r{a}rding polynomials, a class of real multivariate polynomials defined via positivity regions invariant under translation by positive directions and closed under strictly positive affiโ€ฆ

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