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2606.12891 2026-06-12 math.AP math.FA 新提交

Potential Estimates and Hodge Systems with $L^1$ data on compact manifolds

紧流形上具有 $L^1$ 数据的势估计与 Hodge 系统

Jesse Goodman, Felipe Hernández, Daniel Spector

AI总结 本文建立了作用于闭或余闭 $k$-形式的 Riesz 势的最优 Lorentz 估计,并推导了 $k$-形式 Poisson 方程和 Hodge 系统的类似界,回答了 Bourgain 和 Brezis 关于三维环面上 div-curl 系统的公开问题。

Comments 52 pages, 2 appendices

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AI中文摘要

在本文中,我们建立了作用于光滑紧致 $n$ 维黎曼流形上有限质量闭或余闭 $k$-形式的 Riesz 势的最优 Lorentz 估计:对于 $\alpha \in (0,n)$ 和 $k=1,\ldots,n-1$,存在常数 $C>0$ 使得对所有与调和 $k$-形式空间正交且满足 $\mathrm{d} F=0$ 或 $\mathrm{d}^* F=0$ 的 $k$-形式 $F \in L^1(\Lambda^k)$,有 \begin{align*} \| \mathcal{I}_{\alpha,k} F \|_{L^{n/(n-\alpha),1}(\Lambda^k)} \leq C \| F\|_{L^1(\Lambda^k)} \end{align*}。我们展示了这一不等式如何蕴含 $k$-形式 Poisson 方程和具有有限质量数据的 Hodge 系统解的类似 Lorentz 界。这些结果作为特例包含了三维环面上的 div-curl 系统,其中我们回答了 J. Bourgain 和 H. Brezis 最初提出的一个公开问题。

英文摘要

In this paper we establish optimal Lorentz estimates for the Riesz potentials acting on closed or co-closed $k$-forms of finite mass on a smooth, compact Riemannian manifold of dimension $n$: For $α\in (0,n)$ and $k=1,\ldots,n-1$, there exists a constant $C>0$ such that \begin{align*} \| \mathcal{I}_{α,k} F \|_{L^{n/(n-α),1}(Λ^k)} \leq C \| F\|_{L^1(Λ^k)} \end{align*} for all $k$-forms $F \in L^1(Λ^k)$ orthogonal to the space of harmonic $k$-forms and satisfying $\mathrm{d} F=0$ or $\mathrm{d}^* F=0$. We show how this inequality implies analogous Lorentz bounds for solutions of the $k$-form Poisson equation and for the Hodge system with data having finite mass. These results include as a special case the div--curl system on the $3$-dimensional torus, where we answer an open question originally posed by J. Bourgain and H. Brezis.

2606.12888 2026-06-12 cs.IT math.IT 新提交

Pinching-Antenna Enabled Multicell Wireless Systems

夹捏天线赋能的多小区无线系统

Yunshu Chen, Qing Xue, Meng Hua, Bingpeng Zhou, Shaodan Ma

AI总结 研究多波导夹捏天线多小区通信系统,通过联合优化预编码、波导功率分配和天线位置最大化加权和速率,采用交替优化框架和粒子群算法,显著优于传统MIMO方案。

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AI中文摘要

夹捏天线(PA)系统最近成为一种有前景的柔性天线技术,它通过沿介质波导动态调整夹捏元件的位置来重建无线传播环境,从而为增强无线系统性能提供新的空间自由度(DoFs)。本文研究了一种基于多波导PA的多小区通信系统,重点联合优化预编码矩阵、波导功率分配和天线位置以最大化加权和速率(WSR)。在多小区场景中,小区间干扰通常导致高度耦合且非凸的WSR最大化问题。为应对这一挑战,采用了一种高效的交替优化框架,以迭代方式优化每个变量。具体地,首先利用分数规划引入辅助变量解耦信号和干扰项,从而重构原问题。基于此重构,应用块坐标下降法优化预编码矩阵和功率分配,得到闭式或半闭式更新。对于高维且非凸的PA放置问题,采用粒子群优化(PSO)进行高效搜索并提高可扩展性。数值结果表明,在各种系统配置下,所提方案显著优于基线方法,包括平均功率分配、固定天线放置、传统多输入多输出(MIMO)和大规模MIMO。这些结果凸显了PA系统在大规模多小区无线通信中的巨大潜力。

英文摘要

Pinching antenna (PA) systems have recently emerged as a promising flexible-antenna technology, which can reconstruct the wireless propagation environment by dynamically adjusting the positions of pinching elements along dielectric waveguides, thereby providing new spatial degrees of freedom (DoFs) for enhancing wireless system performance. This paper investigates a multi-waveguide PA-based multi-cell communication system, focusing on the joint optimization of precoding matrices, waveguide power allocation, and antenna placement to maximize the weighted sum rate (WSR). In multi-cell scenarios, inter-cell interference typically leads to a highly coupled and nonconvex WSR maximization problem. To address this challenge, an efficient alternating optimization framework is adopted to optimize each variable in an iterative way. Specifically, fractional programming is first employed to reformulate the original problem by introducing auxiliary variables that decouple the signal and interference terms. Based on this reformulation, block coordinate descent is then applied to optimize the precoding matrices and power allocation, leading to closed-form or semi-closed-form updates. For the high-dimensional and nonconvex PA placement problem, particle swarm optimization (PSO) is utilized to perform an efficient search and improve scalability. Numerical results demonstrate that, under various system configurations, the proposed scheme significantly outperforms baseline methods, including average power allocation, fixed antenna placement, conventional multiple-input multiple-output (MIMO), and massive MIMO. These results highlight the strong potential of PA systems for large-scale multi-cell wireless communications.

2606.12880 2026-06-12 math.CO 新提交

Monochromatic $k$ in a row

单色 $k$ 连珠

Kuo-Han Ku

AI总结 研究一种变体 $k$ 连珠游戏,其中玩家交替占据位置直到出现 $k$ 连珠,通过约束近 $k$ 连珠避免配置,确定网格 $\mathbb{Z}^2$ 和超立方体 $[k]^d$ 上的极值密度,给出紧界和精确值。

Comments 24 pages

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AI中文摘要

我们研究了一种 $k$ 连珠游戏的变体,其中玩家交替占据位置,直到所有被占据的位置中出现 $k$ 连珠。这导致了对配置的近 $k$ 连珠避免约束,以及确定此类配置的极值密度的相关问题。我们在两种棋盘上研究这个问题:网格 $\mathbb{Z}^2$ 和超立方体 $[k]^d$。对于网格 $\mathbb{Z}^2$,我们建立了最大密度 $D(k,\mathbb{Z}^2)$ 的几乎紧界,证明当 $3\ mid k$ 时 $D(k,\mathbb{Z}^2)=1-\ rac{2}{k}$,并精确确定了 $D(3,\mathbb{Z}^2)$ 和 $d(3,\mathbb{Z}^2)$。我们还给出了最小密度 $d(k,\mathbb{Z}^2)$ 的界,其差距为 $(8+o(1))k^{-1}$。对于超立方体 $[k]^d$,我们推导出 $D(k,[k]^d)$ 的渐近界,阶为 $k^{-2}$,并得到了 $d(k,[k]^d)$ 的精确值。我们的结果与经典的 no-$(k+1)$-in-line 问题形成对比,后者施加了不同的约束,且其平凡上界被猜想可达。

英文摘要

We study a variant of the $k$-in-a-row game in which players alternatively claim positions until a $k$-in-a-row is created among all claimed positions. This leads to the constraint near $k$-in-a-row avoiding on configurations and the associated problem of determining their extremal densities of such configurations. We investigate this problem on two types of boards: the grid $\mathbb{Z}^2$ and hypercubes $[k]^d$. For the grid $\mathbb{Z}^2$, we establish nearly tight bounds on the maximum density $D(k,\mathbb{Z}^2)$, showing that $D(k,\mathbb{Z}^2)=1-\frac{2}{k}$ whenever $3\nmid k$, and determine both $D(3,\mathbb{Z}^2)$ and $d(3,\mathbb{Z}^2)$ exactly. We also bound the minimum density $d(k,\mathbb{Z}^2)$ up to a gap of $(8+o(1))k^{-1}$. For hypercubes $[k]^d$, we derive asymptotic bounds on $D(k,[k]^d)$ up to order $k^{-2}$ and obtain the exact value of $d(k,[k]^d)$. Our results contrast with the classical no-$(k+1)$-in-line problem, a similar problem imposing different constraint, where the trivial upper bound is conjectured to be attainable.

2606.12875 2026-06-12 math.OC 新提交

Randomized Optimal Switching Problem and Related Mirror Descent Flow

随机化最优切换问题与相关镜像下降流

Yuchao Dong

AI总结 针对最优切换问题,提出随机化框架并引入KL散度正则化,证明正则化值函数是椭圆HJB系统的唯一光滑解,给出最优Gibbs策略的显式形式,并建立镜像下降流算法及收敛误差界。

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AI中文摘要

我们研究最优切换问题的连续时间强化学习,其中决策者通过在有限多个模式间切换来控制扩散过程,并承担运行成本和转移成本。为了进行探索,我们将经典确定性切换控制放宽为随机化框架,其中切换决策由具有状态相关生成元的连续时间马尔可夫链控制,并用温度参数$\lambda$加权的KL散度正则化来增强成本泛函。在系数的温和假设下,我们证明了正则化值函数是椭圆Hamilton-Jacobi-Bellman系统的唯一光滑解,并推导出显式的最优Gibbs策略,该策略由跨模式的值函数差的指数变换给出。我们进一步证明,正则化值函数以$O\left(\lambda \log \frac{1}{\lambda}\right)$阶的误差逼近经典最优值函数,这与在其他熵正则化控制问题中建立的类似界一致,并被认为是紧的。为了数值求解正则化问题,我们在对数量策略空间中引入镜像下降流,证明其适定性以及沿流的值函数单调递减,并建立到经典最优值函数的定量误差界。对于恒定温度调度,收敛速度为$O\left(\frac{1}{e^{\lambda s} - 1}+\lambda \log\frac1\lambda\right)$,而在退火调度$\lambda_s = \frac{1}{\sqrt{1+s}}$下,我们得到速率$O\left(\frac{\log s}{\sqrt{s}}\right)$,随着流时间$s \to \infty$而衰减到零。

英文摘要

We study continuous-time reinforcement learning for the optimal switching problem, in which a decision-maker controls a diffusion process by switching among finitely many regimes, incurring both running and transition costs. To enable exploration, we relax the classical deterministic switching control to a randomized framework, where the switching decisions are governed by a continuous-time Markov chain with state-dependent generator, and augment the cost functional with a KL-divergence regularization weighted by a temperature parameter $λ$. Under mild assumptions on the coefficients, we establish that the regularized value function is the unique smooth solution of an elliptic Hamilton--Jacobi--Bellman system, and derive an explicit optimal Gibbs policy given by an exponential transformation of the value function differences across modes. We further prove that the regularized value function approximates the classical optimal value function with error of order $O\left(λ\log \frac{1}λ\right)$, which is consistent with analogous bounds established in other entropy-regularized control problems and is believed to be sharp. To solve the regularized problem numerically, we introduce a mirror descent flow in the dual logarithmic policy space, prove its well-posedness and the monotonic decrease of the value function along the flow, and establish quantitative error bound to the classical optimal value function. For a constant temperature scheduler, the convergence rate is of order $O\left(\frac{1}{e^{λs} - 1}+λ\log\frac1λ\right)$, while under the annealing scheduler $λ_s = \frac{1}{\sqrt{1+s}}$, we obtain the rate $O\left(\frac{\log s}{\sqrt{s}}\right)$, which decays to zero as the flow time $s \to \infty$.

2606.12868 2026-06-12 math.OC 新提交

Maximum Utility Split Method for Utility Preference Elicitation

最大效用分割方法用于效用偏好引导

Bo Chen, Jia Liu, Huifu Xu

AI总结 提出最大效用分割(MUS)方法,通过最大化效用范围并二分模糊集,逐步逼近真实效用函数,并设计基于线性规划的算法和名义效用函数提取方法。

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AI中文摘要

本文提出了一种新方法,称为最大效用分割(MUS)方案,该方案建立在随机效用分割(RUS)方案之上,但有一个显著区别:一个彩票设计为具有两个固定结果但概率变化,另一个彩票具有确定性结果,该结果特意选择在最大可能效用值与最小可能效用值之间的范围最大的点上。因此,随机彩票的概率被设置为使得该点上效用函数模糊集的范围减半。在适度条件下,我们证明MUS可以连续生成一系列这样的问卷,并有效减少模糊集,最终随着问卷数量的增加收敛到真实效用函数。主要挑战在于有效识别给定由偏好信息构建的模糊集中具有最大效用范围的点。基于模糊集的结构,我们提出了一种基于区间的算法,通过求解一系列线性规划来识别每个确定性结果彩票。此外,为了处理引导在模糊集缩减为单点之前终止的情况,我们展示了如何通过求解优化程序来找出名义效用函数。这些程序在模糊集内识别出Kantorovich度量下的最小和最大效用函数,然后我们识别出位于它们中间的名义效用函数。最后,数值结果证明了MUS方法的效率以及基于MUS类型查询和名义效用引导的机器人顾问系统的性能。虽然主要讨论集中在凹效用函数上,但我们也展示了如何将MUS方法扩展到适应一般非凹效用函数,特别是S形函数。

英文摘要

In this paper, we propose a new approach, called maximum utility split (MUS) scheme, which is built on random utility split (RUS) scheme but with a notable difference: one lottery is designed with two fixed outcomes but with varying probability, and the other has a deterministic outcome specifically chosen at the point where the range between the largest and smallest possible utility values is maximized. Consequently, the probability of random lottery is set such that the range of the ambiguity set of utility functions is reduced by half at the point. Under moderate conditions, we show that MUS can successively generate a sequence of such questionnaires and effectively reduce the ambiguity set, eventually converging to the true utility function as the number of questionnaires increases. The main challenge is to effectively identify the point with the largest utility range for a given ambiguity set constructed from preference information. Based on the structure of the ambiguity set, we propose an interval-based algorithm which identifies each certain-outcome lottery by solving a sequence of linear programs. Moreover, to deal with the case where elicitation terminates before the ambiguity set reduces to a singleton, we demonstrate how to figure out a nominal utility function by solving optimization programs. These identify the smallest and largest utility functions under the Kantorovich metric within the ambiguity set, after which we identify a nominal utility function located in the middle of them. Finally, numerical results demonstrate the efficiency of the MUS method and the performance of a robo-advisor system based on MUS-type queries and the nominal utility elicitation. While the main discussions focus on concave utility functions, we also demonstrate how the MUS approach can be extended to accommodate general non-concave utility functions, particularly S-shaped ones.

2606.12866 2026-06-12 math.OA math.FA 新提交

Rapidly growing AF algebras

快速增长的AF代数

Konrad Aguilar, Stephan Ramon Garcia, Evelyne Knight, Chloe Marple, Jack Spielberg

AI总结 通过数值半群理论中的Bratteli图引入AF代数族,利用Curry-Schoenberg B样条分析其统计性质,并从概率角度研究快速增长AF代数的系综。

Comments 33 pages

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AI中文摘要

我们引入了与数值半群理论(组合学的一个分支)中的Bratteli图相关的某些AF代数族。计算机辅助设计中的基本工具Curry-Schoenberg B样条为这些代数的统计性质提供了洞见。这使得我们可以从概率角度考虑某些“快速增长”AF代数的系综。

英文摘要

We introduce certain families of AF algebras associated to Bratteli diagrams arising from numerical semigroup theory, a branch of combinatorics. Curry-Schoenberg B-splines, staples of computer-aided design, provide insight into the statistical properties of these algebras. This permits us to consider certain ensembles of "rapidly growing" AF algebras from a probabilistic viewpoint.

2606.12865 2026-06-12 math.FA 新提交

On $m$-partial isometries: spectra, weighted shifts, and similarity

关于 $m$-部分等距:谱、加权移位和相似性

Mohamed Amine Aouichaoui, Michał Buchała, Stephan Ramon Garcia

AI总结 本文研究Hilbert空间上的$m$-部分等距算子,建立结构和谱结果,刻画$m$-部分等距加权移位,并探讨与$m$-等距和$m$-部分等距的相似性。

Comments 19 pages

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AI中文摘要

本文旨在研究Hilbert空间上的$m$-部分等距,这是部分等距和$m$-等距的自然推广。我们建立了结构和谱结果,刻画了$m$-部分等距加权移位,并探讨了与$m$-等距和$m$-部分等距的相似性。

英文摘要

The aim of this paper is to study $m$-partial isometries on Hilbert spaces, a natural extension of partial isometries and $m$-isometries. We establish structural and spectral results, characterize the $m$-partial isometric weighted shifts, and investigate similarity to $m$-isometries and $m$-partial isometries.

2606.12861 2026-06-12 math.CO 新提交

Partition-selected flow polynomials and associated arrangements

分区选择的流多项式及相关排列

Beifang Chen, Ying Cao, Houshan Fu, Hongyang Wang

AI总结 提出分区选择方法推广图的流、色和Tutte多项式,通过将标准边子图展开限制在由指定连通顶点分区给出的子图上,建立删除-收缩公式和特化关系,并研究非齐次流与仿射流多项式的关系。

Comments 22 pages

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AI中文摘要

我们引入了一种分区选择方法,通过将标准边子图展开限制在由指定的连通顶点分区给出的子图上,推广了图的流多项式、色多项式和Tutte多项式。我们为这些多项式建立了类似的删除-收缩公式和特化关系,当选择是所有分区的集合时,恢复了所有经典多项式不变量。接下来,我们研究了Jaeger等人的非齐次流与一类特殊的分区选择流多项式(称为仿射流多项式)之间的关系。具体地,我们通过将边坐标排列限制在仿射流空间上,给出了无处为零的非齐次流的几何实现。得到的特征多项式与Kochol的可容许分配多项式以及仿射流多项式一致,后者枚举了有限域上的无处为零的非齐次流。为了看到分区选择框架的关键作用,我们进一步引入了由图的键结构确定的边界排列。利用边界排列的交集偏序集,我们得到了上述所有限制排列的分类、仿射流多项式无符号系数的比较以及仿射流多项式的分解公式。

英文摘要

We introduce a partition-selection method to generalize the flow, chromatic, and Tutte polynomials of a graph by restricting the standard edge subgraph expansions to subgraphs given by prescribed connected vertex partitions. We establish similar deletion-contraction formulas and specialization relations for these polynomials, recovering all classical polynomial invariants when the selection is the set of all partitions. Next we study a relation between Jaeger et al.'s nonhomogeneous flows and a special class of partition-selected flow polynomials (called affine flow polynomials). Specifically, we give a geometric realization of nowhere-zero nonhomogeneous flows by restricting the edge-coordinate arrangement to affine flow spaces. The resulting characteristic polynomials coincide with Kochol's admissible assigning polynomials and with affine flow polynomials, which enumerate nowhere-zero nonhomogeneous flows over finite fields. To see the key role of the partition-selection framework, we further introduce boundary arrangements determined by the bond structure of a graph. Using the intersection posets of boundary arrangements, we obtain the classification of all restricted arrangements mentioned above, the comparison of unsigned coefficients of affine flow polynomials, and the decomposition formulas for affine flow polynomials.

2606.12839 2026-06-12 cs.IT math.IT 新提交

The Capacity Region for Classes of Sum-Broadcast Channels

和广播信道类的容量区域

Amin Gohari, Yi Liu, Chandra Nair

AI总结 本文计算了退化、少噪声、更强能力、确定性或半确定性广播信道之和的容量区域,通过证明辅助接收机外边界匹配Marton内边界,推广了El Gamal的结果。

Comments A conference version will be presented at the 2026 IEEE Symposium on Information Theory

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AI中文摘要

我们计算了其分量为退化、少噪声、更强能力、确定性或半确定性的广播信道之和的容量区域。我们通过证明之前由一些作者引入的辅助接收机外边界与Marton内边界相匹配来实现这一点。该结果推广了El Gamal(1980)关于两个反向退化广播信道之和的已知结果。此外,我们定义了一类主广播信道,并展示了主广播信道之和的类似结果。

英文摘要

We compute the capacity region of a sum of broadcast channels whose components are degraded, less-noisy, more-capable, deterministic, or semi-deterministic. We achieve this by showing that an auxiliary-receiver outer bound, previously introduced by some of the authors, matches Marton's inner bound. This result generalizes a previously known result for the sum of two reversely degraded broadcast channels due to El Gamal (1980). Moreover, we define a class of primary broadcast channels and show an analogous result for the sum of primary broadcast channels.

2606.12833 2026-06-12 math.NA cs.NA 新提交

A Quaternion--BCH Framework for the Local Accuracy of SIDER Interpolation

SIDER 插值局部精度的四元数-BCH 框架

Shingyu Leung

AI总结 本文提出四元数-李代数框架,利用 BCH 展开证明 SIDER-n 插值在均匀采样下对光滑球面曲线具有 O(h^{n+1}) 局部精度。

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AI中文摘要

SIDER-n(阶数为 n 的球面插值)是一种递归高阶插值方法,用于单位球面 $\mathbb{S}^2$ 上的数据,由重复的球面线性插值(SLERP)构建。本文发展了一个四元数-李代数框架,用于证明 SIDER 在等距参数值采样的光滑球面曲线上的局部一致性。球面上的点表示为纯单位四元数,插值误差在固定基的四元数对数坐标中测量。在此设定下,每个 SLERP 操作允许精确的 Baker-Campbell-Hausdorff(BCH)表示,将几何插值问题转化为涉及滤波李多项式展开的代数问题。BCH 展开表明 SLERP 是仿射到主阶的,没有二次修正,第一个非线性修正是三次且为交换子值的。利用这一结构,我们证明 SIDER2 具有三阶分差形式,且主节点因子与普通二次插值相同。然后我们证明递归 SIDER 步骤将阶数提高一阶:仿射部分给出 Neville 型有限差分抵消,而非线性 BCH 余项在移除节点因子后保持锐利的滤波度结构。因此,对于每个固定的 $n\geq2$,在所述光滑性和小模板假设下,有 $d_{\mathbb{S}^2}\bigl(\gamma(\theta h),P_i^{[n]}(\theta;h)\bigr) = O(h^{n+1})$。该证明还识别出主分差系数的平移不变性作为 SIDER 递归背后的代数相容性条件。

英文摘要

Spherical Interpolation of orDER $n$ (SIDER-$n$) is a recursive high-order interpolation method for data on the unit sphere $\mathbb{S}^2$, built from repeated spherical linear interpolation (SLERP). This paper develops a quaternion--Lie algebra framework for proving the local consistency of SIDER for smooth spherical curves sampled at equally spaced parameter values. Points on $\mathbb{S}$ are represented as pure unit quaternions, and interpolation errors are measured in fixed-base quaternion logarithmic coordinates. In this setting, each SLERP operation admits an exact Baker--Campbell--Hausdorff (BCH) representation, which converts the geometric interpolation problem into an algebraic problem involving filtered Lie-polynomial expansions. The BCH expansion shows that SLERP is affine to leading order, has no quadratic correction, and has a first nonlinear correction that is cubic and commutator-valued. Using this structure, we prove that SIDER2 has a third-order divided-error form with the same leading nodal factor as ordinary quadratic interpolation. We then show that the recursive SIDER step raises the order by one: the affine part gives the Neville-type finite-difference cancellation, while the nonlinear BCH remainder preserves the sharp filtered degree structure after the nodal factor is removed. Consequently, for every fixed $n\geq2$, $d_{\mathbb{S}^2}\bigl(γ(θh),P_i^{[n]}(θ;h)\bigr) = O(h^{n+1}) $under the stated smoothness and small-stencil assumptions. The proof also identifies the shift-invariance of the leading divided-error coefficient as the algebraic compatibility condition underlying the SIDER recurrence.

2606.12827 2026-06-12 math.CO cs.DM 新提交

Completely Independent Spanning Trees in $k$-Outerplanar Triangulated Discs

$k$-外平面三角剖分圆盘中的完全独立生成树

Toru Araki

AI总结 本文证明每个3连通2-外平面三角剖分圆盘有两个完全独立生成树,并给出3连通3-外平面三角剖分圆盘存在两个完全独立生成树的充分条件,同时给出一个反例。

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AI中文摘要

设 $T_{1}, T_{2}, \dots, T_{k}$ 是图 $G$ 的 $k$ 棵生成树。对于任意两个顶点 $u$ 和 $v$,如果这 $k$ 棵生成树中的 $u$--$v$ 路径两两内部不相交,则这些生成树称为 $G$ 的完全独立生成树(CISTs)。本文首先证明每个3连通2-外平面三角剖分圆盘有两个完全独立生成树。其次,对于3连通3-外平面三角剖分圆盘 $G$,我们给出了 $G$ 存在两个完全独立生成树的充分条件。我们给出了一个3连通4-外平面三角剖分不具有两个完全独立生成树的例子。

英文摘要

Let $T_{1}, T_{2}, \dots, T_{k}$ be $k$ spanning trees of a graph $G$. For any pair of vertices $u$ and $v$, if the $u$--$v$ paths in the $k$ spanning trees are pairwise openly disjoint, then the spanning trees are called completely independent spanning trees (CISTs) of $G$. In this paper, we first prove that every 3-connected 2-outerplanar triangulated disc has two completely independent spanning trees. Next, for a 3-connected 3-outerplanar triangulated disc $G$, we provide sufficient conditions for $G$ to have two completely independent spanning trees. We provide an example of a 3-connected 4-outerplanar triangulation that does not have two completely independent spanning trees.

2606.12820 2026-06-12 math.PR 新提交

Averaging principles for nonautonomous multiscale McKean-Vlasov stochastic systems

非自治多尺度McKean-Vlasov随机系统的平均原理

Jie Xiang, Huijie Qiao

AI总结 研究非自治多尺度McKean-Vlasov随机系统,利用非自治泊松方程建立强和弱平均原理并给出显式收敛率,在快尺度系数渐近收敛或时间周期条件下慢分量收敛到与ε无关的平均方程。

Comments 46 pages

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AI中文摘要

本文研究了一类非自治多尺度McKean-Vlasov随机系统。通过利用非自治泊松方程,我们严格建立了强和弱平均原理,并给出了显式收敛率。值得注意的是,一般情况下推导出的平均方程的系数仍然依赖于尺度参数$\varepsilon$。然而,在快尺度系数渐近收敛或时间周期的额外假设下,我们证明慢分量在强或弱意义下收敛到系数与$\varepsilon$无关的平均方程。

英文摘要

This paper investigates a class of nonautonomous multiscale McKean-Vlasov stochastic systems. By leveraging the nonautonomous Poisson equation, we rigorously establish both strong and weak averaging principles, accompanied by explicit convergence rates. Notably, the coefficients of the averaging equations derived in the general case retain dependence on the scaling parameter $\varepsilon$. However, under the additional assumptions that the fast-scale coefficients are either asymptotically convergent or time-periodic, we demonstrate that the slow component converges, in the strong or weak sense, to averaging equations with coefficients independent of $\varepsilon$.

2606.12815 2026-06-12 math.AG math.CO 新提交

Fence Complexes and Toric Degenerations of Positroid Varieties

围栏复形与正体种集的托里卡退化

Cameron Chang, Pranav Enugandla, Josephine Hlavinka

AI总结 本文研究了正体种集的围栏复形结构,证明其与闭球同胚,并展示其在正体种集的非负部分上提供正则CW复形结构,同时证明围栏复形的Ehrhart多项式等于相关正体种集的Hilbert多项式。

Comments 54 pages, 14 figures, comments welcome

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AI中文摘要

我们为Grassmannian Gr(k,n)中的每个正体种集关联一个围栏复形,该复形由Gelfand-Tsetlin多面体P_{k,n}的面的并集组成。我们证明这些围栏复形与闭球同胚。此外,它们使Gelfand-Tsetlin多面体具有正则CW复形结构,从而为Gr(k,n)_{≥0}的正则CW复形结构提供多面体复形表示。我们还证明围栏复形的Ehrhart多项式等于相关正体种集的Hilbert多项式。我们证明在Sturmfels-Gonciulea-Lakshmibai退化下,正体种集退化为对应围栏复形的约简的托里卡变种的并集。作为应用,我们分类了包含在钩Schubert变种内的正体种集何时为算术Gorenstein。我们还推导出一个关于循环Demazure模的递归特征公式,该公式等同于Almousa、Gao和Huang的公式。

英文摘要

We associate to each positroid variety in the Grassmannian $\mathrm{Gr}(k,n)$ a polyhedral complex, which we call a fence complex. Fence complexes consist of unions of faces of the Gelfand-Tsetlin polytope $P_{k,n}$ associated to a fundamental weight $ω_k$. We show that these fence complexes are homeomorphic to closed balls. Furthermore, they endow the Gelfand-Tsetlin polytope with the structure of a regular CW complex, giving a polyhedral complex presentation of the regular CW complex structure on $\mathrm{Gr}(k,n)_{\geq 0}$. We also show that the Ehrhart polynomial of a fence complex equals the Hilbert polynomial of the associated positroid variety. We prove that under the Sturmfels-Gonciulea-Lakshmibai degeneration of $\mathrm{Gr}(k,n)$ to the toric variety of the Gelfand-Tsetlin polytope, positroid varieties degenerate to the reduced union of toric varieties corresponding to their fence complexes. As an application, we classify when positroid varieties contained inside hook Schubert varieties are arithmetically Gorenstein. We also derive a recursive character formula for cyclic Demazure modules, which we show is equivalent to a formula of Almousa, Gao and Huang.

2606.12810 2026-06-12 math.NT math.AG 新提交

Splitting of Polynomial Families via Galois Theory

通过伽罗瓦理论的多项式族分裂

Tianhao Wang

AI总结 利用经典伽罗瓦理论和Chebotarev密度定理,研究有限域上参数化多项式族的分裂行为,推广Slavov关于平方值独立性的结果到n次幂剩余,并解释为Kummer扩张的线性无关条件。

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AI中文摘要

我们通过几何和伽罗瓦理论的方法研究有限域上参数化多项式族的分裂行为。尽管底层技术在算术几何中被广泛认为是常识,但很少被明确写出。为了最大化可访问性,我们基于经典伽罗瓦理论和仿射正规簇上的Chebotarev密度定理开发了一个框架,避免了Grothendieck的平展拓扑的繁重机制。主要目标是扩展并概念性地解释Slavov最近的一个结果,该结果建立了有限域上多个多项式的平方值独立的条件。在$q\equiv 1 \pmod n$的情况下,我们将这一现象推广到$n$次幂剩余,并将这个独立条件重新表述为Kummer扩张相互线性无关的自然条件。最后,我们简要提及如何将这些结果转化为平展基本群的现代语言,将基推广到$\mathbb{F}_q$上有限型的几何整正规概形。

英文摘要

We study the splitting behavior of parametrized families of polynomials over finite fields through a geometric and Galois-theoretic approach. While the underlying techniques are widely considered folklore in arithmetic geometry, they have rarely been written down explicitly. To maximize accessibility, we develop a framework based on classical Galois theory and the Chebotarev Density Theorem over an affine normal variety, avoiding the heavy machinery of Grothendieck's étale topology. The primary goal is to extend and conceptually explain a recent result by Slavov, which established the condition for square values of several polynomials over a finite field to be independent. In the case where $q\equiv 1 \pmod n$, we generalize this phenomenon to $n$-th power residues, and reframe this independence condition as the natural condition on Kummer extensions to be mutually linearly disjoint. Finally, we briefly mention how these results can be translated into the modern language of étale fundamental groups, generalizing the base to geometrically integral, normal schemes of finite type over $\mathbb{F}_q$.

2606.12804 2026-06-12 math.DG math.PR 新提交

Sub-Riemannian spectral distance

次黎曼谱距离

Yuzuru Inahama

AI总结 研究紧致等正则次黎曼流形上关于Popp体积的次拉普拉斯算子的特征值与特征函数,并定义两个流形之间的谱距离,这是Riemann情形下Berard-Besson-Gallot工作的次黎曼类比。

Comments 26 pages. No figure

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AI中文摘要

我们研究了紧致等正则次黎曼流形 $M$ 上关于 Popp 体积的“散度-梯度型”次拉普拉斯算子的特征值和特征函数。由于 Popp 体积由 $M$ 的次黎曼结构典范地确定,次拉普拉斯算子的谱具有几何意义。本文首先利用特征函数将 $M$ 嵌入到平方可和序列的 Hilbert 空间中,然后定义了两个紧致等正则次黎曼流形之间的谱距离。我们的结果是 Riemann 情形下 Berard-Besson-Gallot 经典工作的次黎曼类比。

英文摘要

We study eigenvalues and eigenfunctions of the ``div-grad type" sub-Laplacian with respect to Popp's volume on a compact equiregular sub-Riemannian manifold $M$. Since Popp's volume is canonically determined by the sub-Riemannian structure of $M$, the spetra of the sub-Laplacian carry geometric meanings. In this paper, we first embed $M$ into the Hilbert space of square-summable sequences using eigenfunctions and then define a spectral distance between two compact equiregular sub-Riemannian manifolds. Our result is a sub-Riemannian analogue of Berard-Besson-Gallot's classical work in the Riemannian case.

2606.12802 2026-06-12 math.NA cs.NA 新提交

Local Consistency and Higher-Order Structure of Spherical Interpolation

球面插值的局部一致性与高阶结构

Shingyu Leung

AI总结 本文分析球面插值SIDER-n的局部一致性,证明SIDER2、SIDER3、SIDER4分别具有三阶、四阶、五阶精度,并引入度过滤形式展开框架证明一般SIDER-n具有n+1阶精度。

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AI中文摘要

阶数为$n$的球面插值(SIDER-$n$)是一种递归高阶插值构造,用于单位球面$\mathbb{S}^2$上的数据,基于重复的球面线性插值(SLERP)。本文对等距参数值采样的光滑球面曲线进行SIDER的局部一致性分析。分析在测地法坐标中进行,这使得SIDER递归可以与经典Neville插值进行比较,同时保留SLERP引入的曲率相关修正。我们首先推导SLERP的局部展开,并证明SIDER2具有三阶精度;其主导误差与欧几里得二次插值具有相同的移位节点结构。然后我们证明进入SIDER3的相邻SIDER2误差具有共同的主导系数,因此SIDER3递推消去三次项并产生四阶精度。将展开再推高一阶,得到SIDER3的相应系数兼容性,并证明SIDER4的五阶精度。最后,我们为一般SIDER递归引入一个度过滤形式展开框架。该框架证明,对于每个固定的$n$,SIDER-$n$在归一化模板变量中保持所需的多项式度结构。结合$n+1$个节点处的插值条件,在所述光滑性和小模板假设下,得到局部一致性估计$d_{\mathbb{S}^2}\bigl(\gamma(\theta h),P_i^{[n]}(\theta;h)\bigr)=O(h^{n+1})$。

英文摘要

Spherical Interpolation of orDER $n$ (SIDER-$n$) is a recursive high-order interpolation construction for data on the unit sphere $\mathbb{S}^2$, built from repeated spherical linear interpolation (SLERP). This paper gives a local consistency analysis of SIDER for smooth spherical curves sampled at equally spaced parameter values. The analysis is carried out in geodesic normal coordinates, which allows the SIDER recursion to be compared with classical Neville interpolation while retaining the curvature-dependent corrections introduced by SLERP. We first derive local expansions of SLERP and show that SIDER2 has third-order accuracy; its leading error has the same shifted nodal structure as Euclidean quadratic interpolation. We then prove that the adjacent SIDER2 errors entering SIDER3 have a common leading coefficient, so that the SIDER3 recurrence cancels the cubic term and yields fourth-order accuracy. Carrying the expansion one order further gives the corresponding coefficient compatibility for SIDER3 and proves fifth-order accuracy of SIDER4. Finally, we introduce a degree-filtered formal expansion framework for the general SIDER recursion. This framework proves that, for each fixed $n$, SIDER-$n$ preserves the required polynomial degree structure in the normalized stencil variable. Together with the interpolation conditions at the $n+1$ nodes, this yields the local consistency estimate $d_{\mathbb{S}^2}\bigl(γ(θh),P_i^{[n]}(θ;h)\bigr)=O(h^{n+1})$ under the stated smoothness and small-stencil assumptions.

2606.12800 2026-06-12 math.NA cs.NA 新提交

Massively parallel flow routing and drainage area determination

大规模并行流路与流域面积确定

Wolfgang Bangerth

AI总结 针对数字高程模型(DEM)的流路问题,提出一种高效并行算法,能在12288个进程上4秒内处理18.8亿点的大模型。

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AI中文摘要

数字高程模型(DEM)的分辨率和规模已达到仅并行计算机才能高效处理的程度。DEM的一个重要应用是预测水流流向何处,即所谓的“流路问题”(其变体是确定DEM中某点上游的流域面积问题)。传统的流路算法是顺序的,而并行化该方法的尝试迄今仅取得中等成功。本文基于Richardson等人(2014)的早期工作,提出了一种算法及其多种变体,能够高效解决具有大量并行进程的超大模型上的流路问题。对于我们所使用的最大模型(包含18.8亿个点),本文最佳算法能在计算机集群的12288个进程上于4.0秒内完成水流路径计算。

英文摘要

Digital elevation models (DEMs) have reached resolutions and sizes that only parallel computaters can efficiently process. One important application of DEMs is predicting how much water flows where, the so-called ``flow routing problem'' (a variation of which is the problem of determining the drainage area upstream of a point in a DEM). The traditional algorithm for flow routing is sequential, and attempts to parallelize this method have so far only been moderately successful. Herein, we build on earlier work in Richardson et al. (2014) and propose an algorithm and several variations that can efficiently solve the flow routing problem on very large models with very large numbers of parallel processes. For the largest model we use, with 1.88 billion points, the best algorithm herein can route water in 4.0 seconds on 12,288 processes of a computer cluster.

2606.12799 2026-06-12 math.NA cs.NA 新提交

A variable time-step, second-order, and MBP-preserving linear stabilized scheme for the time-fractional Allen-Cahn equation

时间分数阶Allen-Cahn方程的一种变步长、二阶、保持最大界原理的线性稳定格式

Bingyin Zhang, Ao Zhang, Hongfei Fu

AI总结 提出基于变步长Alikhanov公式和中心差分的二阶线性格式,通过显式外推处理非线性项并辅以稳定化技术保持最大界原理,结合离散分数阶Grönwall不等式建立α-鲁棒的最优二阶最大模误差估计,并证明能量稳定性。

Comments 22 pages,7 figures,5 tables

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AI中文摘要

本文针对时间分数阶Allen-Cahn方程,提出了一种基于变步长Alikhanov公式和中心差分离散的二阶线性格式。通过预处理后的二阶外推显式处理非线性势,并借助适当的稳定化技术保持离散最大界原理(MBP)。此外,通过建立离散分数阶Grönwall不等式以及由MBP保证的数值解的一致有界性,我们在初始弱奇异性假设下建立了α-鲁棒且最优的二阶最大模误差估计。同时,证明了能量稳定性,即离散原始能量被初始能量加上一个高阶时空修正项一致有界。最后,通过大量数值实验验证了所提格式的有效性。

英文摘要

In this paper, we present a second-order linear scheme based on the variable-step Alikhanov formula and central difference discretization for the time-fractional Allen-Cahn equation. The nonlinear potential is treated explicitly via a second-order extrapolation with preprocessing, which enables the discrete maximum-bound principle (MBP) to be preserved through an appropriate stabilization technique. Moreover, by developing a discrete fractional Grönwall inequality together with the uniform boundedness of numerical solutions guaranteed by the MBP, we establish an $α$-robust and optimal second-order maximum-norm error estimate under initial weak singularity assumption. In addition, energy stability is proved in the sense that the discrete original energy is uniformly bounded by the initial energy plus a high-order spatiotemporal correction term. Finally, extensive numerical experiments are presented to demonstrate the effectiveness of the proposed scheme.

2606.12786 2026-06-12 math.AP 新提交

Well-posedness and Stability Analysis of Suspension Bridge Models Coupled with Cattaneo Heat Conduction: The Role of Viscoelastic Memory

与Cattaneo热传导耦合的悬索桥模型的适定性与稳定性分析:粘弹性记忆的作用

Jun Zhou, Jiamin He

AI总结 本文利用算子半群理论研究耦合Cattaneo热传导的悬索桥模型,分析无记忆与有粘弹性记忆两种情形,发现无记忆系统具有多项式衰减,而有记忆系统达到指数衰减,表明粘弹性记忆显著增强稳定性。

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AI中文摘要

本文重点研究一类与Cattaneo热传导定律耦合的悬索桥模型,特别关注两种不同情形:具有粘弹性记忆的系统和无记忆的系统。采用算子半群理论作为核心数学工具,对模型的动力学行为进行全面分析。对于无记忆悬索桥系统($\delta = 0$),首先建立其适定性(即解的存在唯一性)。进一步的稳定性分析表明,该系统表现出多项式衰减行为,衰减率取决于桥面结构参数关系:当$\frac{\rho_1}{\kappa} = \frac{\rho_2}{b}$时达到$t^{-1/2}$的衰减率,当$\frac{\rho_1}{\kappa} \neq \frac{\rho_2}{b}$时衰减率减慢至$t^{-1/4}$。此外,在特定系数配置下(即$\chi_0 \neq 0$,或$\chi_0 = 0$且$\chi_1 = 0$,其中$\chi_0, \chi_1$为依赖于参数的系数),指数稳定性被证明无法实现。对于包含粘弹性记忆的对应系统($\delta = 1$),同样验证了解的适定性,更重要的是,系统实现了指数衰减。这表明与无记忆情形相比,粘弹性记忆显著增强了系统稳定性并加速了能量耗散。通过系统探索Cattaneo热传导框架下粘弹性记忆在悬索桥系统稳定性中的调节作用,本研究丰富并扩展了现有关于具有粘弹性记忆的悬索桥模型的研究。

英文摘要

This paper focuses on investigating a class of suspension bridge models coupled with the Cattaneo heat conduction law, with special attention paid to two distinct scenarios: systems with viscoelastic memory and those without. Operator semigroup theory is adopted as the core mathematical tool to conduct a comprehensive analysis of the models' dynamic behaviors. For the memoryless suspension bridge system ($δ= 0$), we first establish its well-posedness (i.e., the existence and uniqueness of solutions). Further stability analysis reveals that this system exhibits polynomial decay behavior, where the decay rate depends on the structural parameter relationship of the bridge deck: a decay rate of $t^{-1/2}$ is achieved when $\frac{ρ_1}κ = \frac{ρ_2}{b}$, and the rate slows down to $t^{-1/4}$ when $\frac{ρ_1}κ \neq \frac{ρ_2}{b}$. Moreover, exponential stability is proven to be unachievable under specific coefficient configurations (i.e., $χ_0 \neq 0$, or $χ_0 = 0$ and $χ_1 = 0$, with $χ_0, χ_1$ being parameter-dependent coefficients). For the counterpart system incorporating viscoelastic memory ($δ= 1$), the well-posedness of solutions is also verified, and more importantly, the system is shown to achieve exponential decay. This indicates that viscoelastic memory significantly enhances system stability and accelerates energy dissipation compared to the memoryless case. By systematically exploring the regulatory role of viscoelastic memory in the stability of suspension bridge systems under the framework of Cattaneo thermal conduction, this study enriches and extends the existing research on suspension bridge models with viscoelastic memory.

2606.12777 2026-06-12 math.OC 新提交

Abstract Dynamic Programming on Partially Ordered Spaces

偏序空间上的抽象动态规划

Chengyuan Peng, John Stachurski, Jingni Yang

AI总结 研究偏序空间上抽象动态规划,通过拓扑稳定性条件(如全局稳定性和策略算子压缩性)保证值迭代、策略迭代等算法的收敛性,并推广到非折扣最优停止和贝叶斯序贯分析等问题。

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AI中文摘要

我们研究偏序空间上的抽象动态规划,将动态规划的序理论方法与拓扑和度量基础相结合。我们证明,易于验证的拓扑稳定性形式,如策略算子的全局稳定性和压缩性,能够提供动态规划的基本最优性性质,以及值函数迭代、Howard策略迭代和乐观策略迭代的收敛性。我们还证明,在非常弱的假设下,平稳策略优于非平稳策略计划。应用包括马尔可夫决策过程、最大化与积分互换的结构估计问题、无折扣最优停止以及贝叶斯序贯分析。对于后两个问题,我们的结果削弱了现有假设,并扩展了基础问题的算法保证。

英文摘要

We study abstract dynamic programs on partially ordered spaces, pairing the order-theoretic approach to dynamic programming with topological and metric foundations. We show that readily verifiable forms of topological stability, such as global stability and contractivity of the policy operators, deliver the fundamental optimality properties of dynamic programming together with convergence of value function iteration, Howard policy iteration, and optimistic policy iteration. We also prove that stationary policies dominate nonstationary policy plans under very weak assumptions. Applications include Markov decision processes, structural estimation problems in which maximization and integration are interchanged, optimal stopping without discounting, and Bayesian sequential analysis. For the last two, our results weaken existing assumptions and extend algorithmic guarantees for foundational problems.

2606.12776 2026-06-12 math.NT 新提交

An AI Proof of 18-Variable Undecidability for Diophantine Equations over $\mathbb Z[i]$

一个关于 $\mathbb Z[i]$ 上丢番图方程 18 变量不可判定性的 AI 证明

Yuchen Ding, Junfeng Li

AI总结 本文通过 AI 证明,在高斯整数环上,不存在算法判定 18 个未知数的多项式方程是否有解,将 Matiyasevich 和 Sun 的 20 变量定理改进为 18 变量。

Comments Part of the proofs in this paper have been verified by Lean

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AI中文摘要

本文给出了一个 AI 证明,证明不存在算法可以判定高斯整数环上 18 个未知数的多项式方程是否有解。该证明改进了 Matiyasevich 和 Sun 的 20 变量定理。它遵循他们的有理数准则和整数检验,但节省了两个变量:通过施加两个整数条件避免了分母消去变量,并且通过单变量技巧 $(2R+1)(3R+1)$ 将剩余的非零条件吸收到关系组合引理中。

英文摘要

This paper presents an AI proof that there is no algorithm deciding whether a polynomial equation over the Gaussian integers in $18$ unknowns has a solution. The proof improves the $20$-unknown theorem of Matiyasevich and Sun. It follows their rationality criterion and integer test, but saves two variables: the clearing-denominator variable is avoided by imposing two integer conditions, and the remaining nonzero condition is absorbed into the relation-combining lemma by the one-variable gadget $(2R+1)(3R+1)$.

2606.12771 2026-06-12 math.AP 新提交

Elliptic criticality versus Volterra memory in indirect chemotaxis cascades

间接趋化级联中的椭圆临界性与Volterra记忆

Louis Shuo Wang

AI总结 研究间接趋化级联中两种渐近机制:椭圆-椭圆极限下自伴四阶算子的谱正性、熵耗散和临界空间L^{N/4},以及混合椭圆-抛物级联中Volterra记忆算子的临界理论需基于时空估计。

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AI中文摘要

间接信号产生通常被视为经典Keller-Segel趋化性的高阶变体,但其临界结构强烈依赖于信号级联的闭合方式。本文分离了两阶段信号机制的两种渐近区域。在抛物-椭圆-椭圆极限下,趋化剂由自伴四阶算子$K_\tau=(I-\tau\Delta)^{-1}(I-\Delta)^{-1}$生成。我们证明了其谱正性、熵耗散结构、四阶主尺度以及四维中的对数核奇异性。因此,正确的临界空间是$L^{N/4}$,且$N=4$是质量临界维数。浓度计算确定了自然阈值候选$M_* = 64\pi^2\tau/\chi$,而尖锐阈值定理被表述为一个Adams/对数-HLS开放问题。相反,混合椭圆-抛物级联不能简化为静态四阶核。其消除的信号是一个Volterra记忆算子,其近对角乘子与经典Keller-Segel漂移具有相同的阶。因此其临界理论必须基于混合时空估计,而非静态椭圆尺度。数值实验支持我们的算子级区分。

英文摘要

Indirect signal production is often treated as a higher-order variant of classical Keller-Segel chemotaxis, but its critical structure depends strongly on how the signal cascade is closed. This paper separates two asymptotic regimes of a two-stage signalling mechanism. In the parabolic--elliptic--elliptic limit, the chemoattractant is generated by the self-adjoint fourth-order operator $K_τ=(I-τΔ)^{-1}(I-Δ)^{-1}$. We prove its spectral positivity, entropy-dissipation structure, fourth-order principal scaling, and logarithmic kernel singularity in four dimensions. Consequently, the correct critical space is $L^{N/4}$, and $N=4$ is the mass-critical dimension. A concentration calculation identifies the natural threshold candidate $M_* = 64π^2τ/χ$, while the sharp threshold theorem is formulated as an Adams/logarithmic-HLS open problem. In contrast, the mixed elliptic--parabolic cascade cannot be reduced to a static fourth-order kernel. Its eliminated signal is a Volterra memory operator whose near-diagonal multiplier has the same order as the classical Keller-Segel drift. Thus its critical theory must be based on mixed space--time estimates, not static elliptic scaling. Numerical experiments support our operator-level distinction.

2606.12757 2026-06-12 math.AP 新提交

On the weak formulation of Prandtl's minimum drag problem

关于普朗特最小阻力问题的弱形式

Aram L. Karakhanyan, Yigit Katgi

AI总结 在分数阶Sobolev空间H^{1/2}中研究普朗特诱导阻力最小化问题,通过变分法证明解的存在唯一性并推导欧拉-拉格朗日方程。

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AI中文摘要

我们研究普朗特关于固定展长有限翼诱导阻力最小化的经典问题。诱导阻力由环量的奇异二次泛函给出,容许函数满足给定的升力和二阶矩条件。我们在分数阶Sobolev空间\(H^{1/2}\)中表述该问题,这是该泛函的自然能量空间,通过变分法证明极小值的存在唯一性,并推导相应的欧拉-拉格朗日方程。

英文摘要

We study Prandtl's classical problem on minimising the induced drag for a finite wing with fixed span. The induced drag is given by a singular quadratic functional of the circulation, with admissible functions satisfying the prescribed lift and second-moment conditions. We formulate the problem in the fractional Sobolev space \(H^{1/2}\), which is the natural energy space for the functional, prove existence and uniqueness of minimisers by variational methods, and derive the corresponding Euler--Lagrange equation. % Passing to a periodic formulation on the one-dimensional torus, we identify the drag functional with the quadratic form of the half-Laplacian and solve the resulting singular integral equation explicitly and recover Prandtl's bell-shaped circulation profile.

2606.12756 2026-06-12 math.AP 新提交

Invisible Defect Cascades for Navier-Stokes Regularity

Navier-Stokes正则性的不可见缺陷级联

Runlong Yu

AI总结 针对三维不可压缩Navier-Stokes方程局部正则性问题,提出条件性尺度临界缺陷级联约化定理,通过二进尺度重标度、粗粒化、压力分裂等技术,将奇异点归约为不可见缺陷级联,并给出正则性判据。

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AI中文摘要

我们为三维不可压缩Navier-Stokes方程的局部正则性问题制定了一个条件性的尺度临界缺陷级联约化。该定理涉及一个潜在奇异点,对于该点,没有足够小的二进尺度进入Caffarelli-Kohn-Nirenberg小性区域。在该框架的结构性假设下,这样的点不能由未微分的能量或压力集中来解释。它必须导致非有效的移动窗口可观测性,或者导致一个NS可实现的、清理过的、尺度临界缺陷级联,该级联对联合主动压力、通量、能量和伴随迹测试不可见。该约化基于二进重标度、粗粒化、主动/调和压力分裂、Reynolds协方差正性、压力相容性和局部能量-通量恒等式。有限窗口可观测性将可能的不可见方向约化为显式定义的剩余核,而预算相容性和符号一致性将可见的压力-通量活动转化为消耗。因此,在一个受控的窗口类中,其中二进缺陷提取、可观测消耗和移动窗口增长控制成立,有效的可观测性连同排除NS可实现的联合不可见级联产生一个CKN尺度,从而得到局部正则性。最后一部分将剩余的障碍解释为一个临界递归问题,并提出了涡旋拉伸、主动压力功和尺度间通量的诊断方法。空间调和压力被保留为物理局部压力分量;只有纯时间依赖的压力函数被视为规范。

英文摘要

We formulate a conditional scale-critical defect-cascade reduction for the local regularity problem of the three-dimensional incompressible Navier--Stokes equations. The theorem concerns a potential singular point for which no sufficiently small dyadic scale enters the Caffarelli--Kohn--Nirenberg smallness regime. Under the structural hypotheses of the framework, such a point cannot be explained by an undifferentiated concentration of energy or pressure. It must lead either to non-effective moving-window observability or to an NS-realizable, cleaned, scale-critical defect cascade invisible to the combined active-pressure, flux, energy, and adjoint-trace tests. The reduction is built from dyadic rescaling, coarse graining, active/harmonic pressure splitting, Reynolds covariance positivity, pressure compatibility, and local energy-flux identities. Finite-window observability reduces possible invisible directions to explicitly defined residual kernels, while budget compatibility and sign coherence convert visible pressure--flux activity into depletion. Consequently, within a controlled window class where dyadic defect extraction, observable depletion, and moving-window growth control hold, effective observability together with exclusion of NS-realizable combined-invisible cascades yields a CKN scale and hence local regularity. The final component interprets the remaining obstruction as a critical recurrence problem and proposes diagnostics for vortex stretching, active pressure work, and interscale flux. Spatially harmonic pressure is retained as a physical local pressure component; only purely time-dependent pressure functions are treated as gauge.

2606.12751 2026-06-12 math.CO 新提交

Nordhaus-Gaddum upper bounds for graph connectivity parameters

图连通性参数的Nordhaus-Gaddum上界

Mark Kempton, Xavier Zaitzeff, Sibi Muthuprakash

AI总结 研究图连通性相关参数的Nordhaus-Gaddum型上界,证明对于n个顶点且图及其补图均连通的图,代数连通度之和不超过n-3(有限个顶点数较小的图例外),并得到等周数、Cheeger常数和正规化拉普拉斯矩阵第二特征值的类似结果。

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AI中文摘要

我们研究了图连通性相关参数的Nordhaus-Gaddum型问题的上界。主要结果是:对于n个顶点上的图$G$,若$G$及其补图$G^c$均连通,则$G$的代数连通度与$G^c$的代数连通度之和不超过$n-3$(有限个顶点数较小的图例外)。我们得到了图的等周数的类似结果,并探讨了Cheeger常数和正规化拉普拉斯矩阵的第二特征值的类似Nordhaus-Gaddum型问题。

英文摘要

We examine upper bounds on Nordhaus-Gaddum type problems for parameters related to graph connectivity. Our main result is that for a graph $G$ on $n$ vertices where both $G$ and its complement $G^c$ are connected, then the sum of the algebraic connectivity of $G$ and the algebraic connectivity of $G^c$ cannot exceed $n-3$ (with finitely many exceptions with a small number of vertices). We obtain similar results for the isoperimetric number of a graph, and explore similar Nordhaus-Gaddum type questions for the Cheeger constant and the second eigenvalue of the normalized Laplacian matrix.

2606.12746 2026-06-12 math.FA math.LO 新提交

Constructive Notes on Locally Convex Spaces

局部凸空间的构造性注释

Douglas S. Bridges

AI总结 本文详细纠正了局部凸空间构造性理论的一些基础,这些基础在<cite>BVtech</cite>中未给出证明,并为最终章节的重要泛函分析定理提供基础。

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AI中文摘要

我们给出了局部凸空间构造性理论的一些基础的详细、纠正后的表述,这些基础在<cite>BVtech</cite>中未给出证明。这足以证明我们最后一节中陈述的一些重要的泛函分析定理。

英文摘要

We give a detailed, corrected presentation of some fundamentals of the constructive theory of locally convex spaces that appear without proofs in <cite>BVtech</cite>. This suffices for some important functional analytic theorems that are stated in our final section.

2606.12745 2026-06-12 math.DG math.SP 新提交

A Large-Diameter Fundamental-Gap Lower Bound for Horoconvex Domains

Horoconvex 区域的大直径基本间隙下界

Xianzhe Dai, John Ennis, Xuan Hien Nguyen, Guofang Wei

AI总结 针对曲率为-1的实双曲空间中紧致horoconvex区域,通过几何归约和径向-高度定理,证明基本间隙的D^{-3}尺度下界,匹配已知上界。

Comments 59 pages

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AI中文摘要

我们证明了曲率为-1的实双曲空间中紧致horoconvex区域的大直径基本间隙下界。几何部分将大horoconvex区域归约为所有维度上的固定宽度径向-高度问题。解析部分通过将低能量Dirichlet形式与球面上的极限角算子进行比较,同时径向补集由一维分支间隙和端点Green估计分离,证明了所需的径向-高度定理。结果给出了多项式D^{-3}尺度,匹配Nguyen--Stancu--Wei的大直径上界。

英文摘要

We prove a large-diameter fundamental-gap lower bound for compact horoconvex domains in real hyperbolic space of curvature \(-1\). The geometric part reduces large horoconvex domains to a fixed-width radial-height problem in all dimensions. The analytic part proves the needed radial-height theorem by comparing the low-energy Dirichlet form with a limiting angular operator on the sphere, while the radial complement is separated by a one-dimensional branch gap and endpoint Green estimates. The result gives the polynomial \(D^{-3}\) scale matching the Nguyen--Stancu--Wei large-diameter upper bound.

2606.12729 2026-06-12 math.SG 新提交

Quadrilateral mutations and symplectic embeddings

四边形突变与辛嵌入

Nicki Magill

AI总结 研究几乎环面基图、完美例外类和最优椭球嵌入之间的关系,通过递归三元组编码非Delzant角,证明突变对应代数突变,并应用于椭球嵌入问题。

Comments 67 pages, 2 figure, comments welcome!

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AI中文摘要

我们研究了$H_b=\mathbb{CP}^2_1 \# \overline{\mathbb{CP}\!}\,{}^2_b$和$P_b=S^2_1\times S^2_b$的几乎环面基图、完美例外类和最优椭球嵌入之间的关系。从一个具有一个Delzant角的四边形几乎环面基图出发,我们通过一个递归三元组编码三个非Delzant角。我们证明,通过从初始图进行明确定义的突变序列得到的每个四边形,都以相同的方式由递归三元组编码。此外,这些图的几何突变对应于相关三元组的代数突变。这些代数突变是用于生成$H$的$(p,q)$-完美类的递归操作。我们应用这个字典,通过显式的几乎环面突变序列,为$b$的适当值实现$H$的每个$(p,q)$-完美类。我们还证明了$P$的拟完美类三元组的类似实现结果,表明这些类实际上是$(p,q)$-完美的。最后,我们将这些结果应用于椭球嵌入问题,包括可见嵌入、可见障碍和ATF-可见阶梯。

英文摘要

We study the relationship between almost toric base diagrams, perfect exceptional classes, and optimal ellipsoid embeddings for $H_b=\mathbb{CP}^2_1 \# \overline{\mathbb{CP}\!}\,{}^2_b$ and $P_b=S^2_1\times S^2_b$. Starting from a quadrilateral almost toric base diagram with one Delzant corner, we encode the three non-Delzant corners by a recursive triple. We show that every quadrilateral obtained via a well-defined sequence of mutations from the initial diagrams is encoded by a recursive triple in the same way. Moreover, geometric mutation of these diagrams corresponds to algebraic mutation of the associated triples. These algebraic mutations are the recursive operations used to generate the $(p,q)$-perfect classes for $H$. We apply this dictionary to realize every $(p,q)$-perfect class for $H$ by an explicit sequence of almost toric mutations for suitable values of $b$. We also prove the analogous realization result for triples of quasi-perfect classes for $P$, showing that these classes are in fact $(p,q)$-perfect. Finally, we apply these results to ellipsoid embedding problems, including visible embeddings, visible obstructions, and ATF-visible staircases.

2606.12725 2026-06-12 math.CO 新提交

On partially matchable subspaces in a field extension

域扩张中的部分匹配子空间

Mohsen Aliabadi, Jozsef Losonczy

AI总结 本文在域扩张的线性框架下,引入有限维K-子空间间的部分匹配概念,并证明与阿贝尔群中部分匹配存在性定理平行的线性版本,融合线性代数与拟阵横贯理论。

Comments Comments welcome

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AI中文摘要

我们阐述并证明了阿贝尔群中有限子集间部分匹配结果的线性对应。在群论背景下,存在适当假设下部分匹配存在的充要条件;我们的目标是在线性框架中获得平行结论。特别地,对于域扩张 $K\subsetneq L$,我们引入了有限维 $K$-子空间 $A,B\subseteq L$ 之间的部分匹配概念,并证明了反映阿贝尔群子集已知结果的存在性定理。在此过程中,我们恢复并扩展了匹配理论这一领域的多个部分,强调了群论与线性设定之间的紧密类比。我们的方法融合了经典线性代数技术与拟阵横贯理论工具,并利用了源自加性数论的一种方法的线性化版本。

英文摘要

We formulate and prove linear counterparts of results on partial matchings between finite subsets in abelian groups. In the group setting, there are necessary and sufficient criteria for the existence of partial matchings under suitable hypotheses; our aim is to obtain parallel statements in a linear framework. In particular, for a field extension $K\subsetneq L$ we introduce a notion of partial matching between finite-dimensional $K$-subspaces $A,B\subseteq L$, and we prove existence theorems mirroring known results for subsets of abelian groups. Along the way, we recover and extend various parts of this area of matching theory, emphasizing the close analogy between the group-theoretic and linear settings. Our approach blends classical linear-algebraic techniques with tools from matroidal transversal theory, and utilizes a linearized version of a method originating in additive number theory.

2606.12722 2026-06-12 math.FA math.CV 新提交

Finite-sheeted Cauchy operator at rational corners

有理角点处的有限叶柯西算子

Louis Shuo Wang

AI总结 研究平面楔形区域上开口角为π的有理倍数的柯西奇异积分算子,通过覆盖变换将其分解为区间柯西变换的有限叶组合,并分析其函数空间性质和端点展开。

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AI中文摘要

我们研究平面楔形区域上的柯西奇异积分算子,其开口角为$\pi$的有理倍数。对于$\theta=p\pi/q$,覆盖$w=\zeta^q$给出了楔形柯西变换到$2q$个区间柯西变换的精确有限叶分解,并带有显式的代数重组系数。该分解在加权共法Hölder空间上表述。我们证明提升算子保持共法阶,将Hölder指数从$\beta$降低到$\beta/q$,并具有尖锐的$\ell^1$叶范数$q$。将该算子分解与区间柯西变换的Mellin模型相结合,我们推导出多齐次端点展开的逐模传播规则。非共振幂保持其对数阶,而整数指数则将其提高一阶。该结果还给出了具有有理角点的分段解析曲线上柯西算子的局部奇异分解。

英文摘要

We study Cauchy singular integral operators on planar wedges whose opening angle is a rational multiple of $π$. For $θ=pπ/q$, the covering $w=ζ^q$ yields an exact finite-sheeted factorization of the wedge Cauchy transform into $2q$ interval Cauchy transforms with explicit algebraic recombination coefficients. The factorization is formulated on weighted conormal Hölder spaces. We prove that the lifting operator preserves conormal order, lowers the Hölder exponent from $β$ to $β/q$, and has sharp $\ell^1$ sheet norm $q$. Combining this operator factorization with a Mellin model for interval Cauchy transforms, we derive a mode-by-mode propagation rule for polyhomogeneous endpoint expansions. Nonresonant powers preserve their logarithmic order, while integer exponents raise it by one. The results also give a local singular decomposition for Cauchy operators on piecewise analytic curves with rational corner angles.