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2606.09825 2026-06-09 cs.LG cs.AI cs.SY eess.SY math.OC 新提交

An Agency-Transferring Model-Free Policy Enhancement Technique

一种无模型策略增强的代理转移技术

Anton Bolychev, Georgiy Malaniya, Sinan Ibrahim, Pavel Osinenko

发表机构 * Center for Engineering Systems and Sciences(工程系统与科学中心) Central University(中央大学) Sirius University of Science and Technology(天狼星科技大学)

AI总结 提出一种将次优基线策略嵌入强化学习训练的方法,通过逐步从基线策略向可学习策略转移代理权,提升训练效率并最终获得超越基线的独立策略。

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AI中文摘要

从头开始训练强化学习(RL)策略成本高昂:需要仔细设计奖励和环境、大量调参以及大量计算。然而,许多控制问题已经有一个功能正常但次优的基线策略可用。本文提出一种方法,将这样的基线策略嵌入RL训练过程,同时提高相对于从头开始方法的训练效率,并产生一个优于基线的学习策略。在每个步骤中,该方法在基线策略和可训练的学习策略之间进行仲裁,最初强烈依赖基线策略,然后逐步将代理权转移给学习策略。训练结束时,学习策略是一个无需基线策略支持的独立神经网络。本文形式化了基线策略“功能正常”的含义:在该策略下,智能体以高概率到达目标集并停留在那里。所提出的仲裁机制旨在训练过程中利用这一特性,从训练开始就产生高目标到达率。理论分析在给定假设下提供了这种行为的形式化解释,并将其扩展到最终无基线场景,其中推导了独立学习策略目标到达概率的显式下界。在连续控制基准上的实验结果表明,所提出的方法实现了与竞争方法相当或更高的回报,同时在训练过程中(包括最终阶段,学习策略无需任何基线支持)保持了最高的目标到达率。

英文摘要

Training reinforcement learning (RL) policies from scratch is costly: it requires careful reward and environment design, extensive tuning, and substantial computation. Yet many control problems already have a functional but suboptimal policy available as a baseline. This paper proposes a method for embedding such a baseline into the RL training process, simultaneously improving training efficiency relative to from-scratch methods and producing a learning policy that outperforms the baseline. At each step, the method arbitrates between the baseline policy and a trainable learning policy, initially relying strongly on the baseline policy and then progressively transferring agency to the learning policy. By the end of training, the learning policy is a standalone neural network that operates without baseline policy support. The paper formalizes what it means for the baseline policy to be functional: under this policy, the agent reaches a goal set and remains there with high probability. The proposed arbitration mechanism is designed to exploit this property during training, yielding high goal-reaching rates right from the beginning of training. A theoretical analysis provides a formal interpretation of this behavior under stated assumptions and extends it to the final baseline-free regime, where explicit lower bounds are derived for the goal-reaching probability of the standalone learning policy. Empirical results on continuous-control benchmarks show that the proposed method achieves returns that match or exceed those of competitive approaches, while maintaining the highest goal-reaching rates throughout training among the compared methods -- including in the final stage, where the learning policy operates without any baseline support.

2606.09820 2026-06-09 math.FA cs.LG math.PR q-fin.MF stat.ML 新提交

Weighted universal approximation of differentiable maps on infinite-dimensional manifolds

无限维流形上可微映射的加权通用逼近

Philipp Schmocker, Josef Teichmann

AI总结 通过加权Nachbin定理,将函数输入神经网络的通用逼近定理推广到可微映射,包括导数逼近,并应用于非预期泛函和路径空间泛函的逼近。

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77 pages, 3 figures
AI中文摘要

我们将函数输入神经网络(FNN)的通用逼近定理推广到可微映射,包括导数的逼近。FNN将输入从可能无限维的加权流形映射到实值隐藏层,在该层上应用非线性标量激活函数,然后通过一些线性读出将输出返回到Banach空间。通过证明加权Nachbin定理,我们建立了可微映射的通用逼近定理(UAT),该定理超越了紧集上的通常表述,并且还包括导数的逼近。这导致了非预期泛函(包括水平和垂直导数)的逼近结果。作为进一步的应用,我们证明了签名的线性函数能够逼近路径空间泛函,包括它们的方向导数。

英文摘要

We generalize the universal approximation theorem for functional input neural networks (FNN) to differentiable maps by including the approximation of the derivatives. A FNN maps the input from a possibly infinite-dimensional weighted manifold to the real-valued hidden layer, on which a non-linear scalar activation function is applied, and then returns the output into a Banach space via some linear readouts. By proving a weighted Nachbin theorem, we establish a universal approximation theorem (UAT) for differentiable maps, which goes beyond the usual formulation on compact sets and also includes the approximation of the derivatives. This leads us to approximation results for non-anticipative functionals including the horizontal and vertical derivatives. As a further application, we show that linear functions of the signature are able to approximate path space functionals including their directional derivatives.

2606.09818 2026-06-09 math.NT 新提交

A note on large values of Dirichlet $L$-functions for characters of fixed order at $1/2<σ\leq 1$

关于固定阶特征在 $1/2<σ\leq 1$ 处 Dirichlet $L$-函数大值的一个注记

Youness Lamzouri

AI总结 本文通过简单论证,证明了固定阶本原特征的 Dirichlet $L$-函数在 $σ\in (1/2,1]$ 处存在推测性尖锐大小的大值,并给出了显式常数。

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7 pages
AI中文摘要

在这篇注记中,我们使用一个简单的论证来证明,对于固定阶的本原特征,在 $σ\in (1/2, 1]$ 处,Dirichlet $L$-函数存在推测性尖锐大小的大值。更精确地说,对于每个固定的整数 $g\geq 2$,我们证明存在一个阶为 $g$、导子 $Q\asymp x$ 的本原特征 $χ$,使得 $|L(1,χ)| \geq e^γ\left(\log\log x+\log\log\log x-\log(2\log g)+o(1)\right).$ 我们还证明,对于每个固定的 $1/2<σ<1$,存在一个阶为 $g$、导子 $Q\asymp x$ 的本原特征 $χ$,使得 $\log |L(σ,χ)| \geq \left(C_g(σ)+o(1)\right) (\log x)^{1-σ}(\log\log x)^{-σ},$ 其中 $C_g(σ)$ 是某个显式正常数。此前,这些界限仅在广义黎曼假设下已知,且仅对特殊情况 $g=2$ 和 $g=3$ 成立。

英文摘要

In this note, we use a simple argument to show the existence of large values of conjecturally sharp size for Dirichlet $L$-functions attached to primitive characters of fixed order at $σ\in (1/2, 1]$. More precisely, for every fixed integer $g\geq 2$ we prove the existence of a primitive character $χ$ of order $g$ and conductor $Q\asymp x$ such that $|L(1,χ)| \geq e^γ\left(\log\log x+\log\log\log x-\log(2\log g)+o(1)\right). $ We also show that for every fixed $1/2<σ<1$ there exists a primitive character $χ$ of order $g$ and conductor $Q\asymp x$ such that $\log |L(σ,χ)| \geq \left(C_g(σ)+o(1)\right) (\log x)^{1-σ}(\log\log x)^{-σ}, $ for some explicit positive constant $C_g(σ).$ Previously, such bounds were known only conditionally on the Generalized Riemann Hypothesis, and even then only in the special cases $g=2$ and $g=3$.

2606.09816 2026-06-09 cs.CV cs.AI math.PR 新提交

PTL-Diffusion: Manifold-Aware Diffusion with Periodic Terminal Laws

PTL-Diffusion: 具有周期终端定律的流形感知扩散

Danqi Zhuang, Jisui Huang, Xiaoyue Xi, Andrew Kiggins, Xiaojie Wang, Ke Chen, Yue Wu

发表机构 * University of Pennsylvania(宾夕法尼亚大学) University of Cambridge(剑桥大学) University of Oxford(牛津大学) Harvard University(哈佛大学) MIT(麻省理工学院) University of Washington(华盛顿大学)

AI总结 提出PTL-Diffusion,通过将前向噪声过程收敛到周期高斯终端族而非单一分布,显式嵌入相位结构,改善低维流形上的分布匹配,在点云和人脸数据集上降低误差。

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AI中文摘要

标准扩散模型通常使用单一时间齐次高斯终端分布作为生成的参考律。虽然这一选择在分析上方便且经验上有效,但对于集中在低维流形附近的数据,它提供的显式结构很少,其中数据分布的不同区域可能对应于不同的局部几何或语义因素。因此,反向模型必须几乎完全从非结构化的终端参考分布中恢复流形级别的结构。\n我们提出PTL-Diffusion,一种概念验证的扩散框架,其前向噪声过程收敛到一个非常数的周期高斯终端族,而不是单一不变律。与相位条件DDPM不同(其中相位信息仅进入去噪网络,而前向过程保持不变),PTL-Diffusion将相位结构直接嵌入前向噪声动力学中。\n所提出的构造仍然接近标准去噪扩散模型:对于周期强迫的Ornstein-Uhlenbeck型前向过程,我们推导出闭合形式的前向边际分布、极限周期高斯终端族以及显式高斯反向后验,从而支持标准噪声预测训练。我们还引入了一个不变平均正则化项,通过平均周期参考律耦合相位条件反向动力学。在环面和圆柱点云基准以及Olivetti人脸数据集上的实验表明,PTL-Diffusion在匹配的DDPM基线上改善了流形级别的分布匹配,减少了相位条件误差、特征空间协方差误差和最近邻流形距离。这些结果表明结构化终端参考律是一个有前景的方向,同时激励更具表现力的相位构造和更大规模的评估。

英文摘要

Standard diffusion models typically use a single time-homogeneous Gaussian terminal distribution as the reference law for generation. While this choice is analytically convenient and empirically powerful, it provides little explicit structure for data concentrated near low-dimensional manifolds, where different regions of the data distribution may correspond to distinct local geometric or semantic factors. As a result, the reverse model must recover manifold-level structure almost entirely from an unstructured terminal reference distribution. We propose PTL-Diffusion, a proof-of-concept diffusion framework whose forward noising process converges to a nonconstant periodic family of Gaussian terminal laws rather than to a single invariant law. Unlike a phase-conditioned DDPM, where phase information only enters the denoising network while the forward process remains unchanged, PTL-Diffusion embeds phase structure directly into the forward noising dynamics. The proposed construction remains close to standard denoising diffusion models: for a periodically forced Ornstein--Uhlenbeck-type forward process, we derive closed-form forward marginals, the limiting periodic Gaussian terminal family, and explicit Gaussian reverse posteriors, enabling standard noise-prediction training. We also introduce an invariant-average regularization term coupling the phase-conditioned reverse dynamics through the averaged periodic reference law. Experiments on torus and cylinder point-cloud benchmarks and the Olivetti face dataset show that PTL-Diffusion improves manifold-level distributional matching over matched DDPM baselines, reducing phase-conditioned errors, feature-space covariance errors, and nearest-neighbour manifold distances. These results suggest structured terminal reference laws as a promising direction, while motivating more expressive phase constructions and larger-scale evaluations.

2606.09815 2026-06-09 math.OC math.PR 新提交

Limit Theory for $N$-Player $α$-Potential Games

$N$ 玩家 $\alpha$-势博弈的极限理论

Xin Guo, Meng Wang, Yufei Zhang

AI总结 研究 $N$ 玩家 $\alpha$-势博弈当 $N\to\infty$ 时的极限行为,证明其收敛到势平均场博弈,并建立 $\lim_{N\to\infty}\alpha_N=0$ 与势平均场博弈存在条件的等价性,同时利用 Wasserstein 空间微分几何构造势函数。

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AI中文摘要

$\alpha$-势博弈框架最近被引入作为分析有限玩家动态博弈的工具,将寻找近似纳什均衡的挑战性任务简化为最小化单个函数(称为 $\alpha$-势函数)的控制问题。本文研究了当玩家数量 $N$ 趋于无穷时 $\alpha$-势博弈的极限行为。我们证明势平均场博弈(MFGs)自然地作为这一极限出现。具体地,归一化的 $N$ 玩家 $\alpha_N$-势函数的最优值和极小化子都收敛到具有测度值控制的平均场控制(MFC)问题的最优值和极小化子。我们建立了 $\lim_{N\to\infty}\alpha_N= 0$ 与势 MFGs 现有条件的等价性,并提供了利用 Wasserstein 空间微分几何技术构造 MFGs 势函数的统一方法。我们进一步证明极限 MFC 问题的目标函数作为相应 MFGs 的势函数,这是有限玩家情形的推广。这一联系通过渐近条件 $\lim_{N\to \infty}\alpha_N= 0$ 从有限玩家博弈得到了势 MFGs 的新构造。作为副产品,我们建立了对于具有共同噪声和非可分离控制相互作用的受控扩散,收敛到 MFGs 的 $N$ 玩家博弈的混沌传播。

英文摘要

The framework of $α$-potential games has recently been introduced as a tool to analyze finite-player dynamic games, reducing the challenging task of finding approximate Nash equilibria to a control problem of minimizing a single function called $α$-potential function. In this work, we investigate the limiting behavior of $α$-potential games as the number of players $N$ tends to infinity. We show that potential mean field games (MFGs) arise naturally as this limit. Specifically, both the optimal values and the minimizers of normalized $N$-player $α_N$-potential functions converge to those of a mean field control (MFC) problem with measure-valued controls. We establish the equivalence of $\lim_{N\to\infty}α_N= 0$ with the existing conditions for potential MFGs, and provide an unified approach to construct the potential function for MFGs using the techniques from differential geometry in Wasserstein space. We further demonstrate that the objective of the limiting MFC problem serves as a potential function for the corresponding MFGs, an extension of the analogous finite-player setting. This connection yields new constructions of potential MFGs from a finite-player game, through the asymptotic condition $\lim_{N\to \infty}α_N= 0$. As a by-product, we establish propagation of chaos for $N$-player games converging to MFGs for general controlled diffusions with common noise and non-separable control interactions.

2606.09808 2026-06-09 math.AP 新提交

High Mach number limit of the compressible Navier--Stokes equations in critical Besov spaces

临界Besov空间中可压缩Navier-Stokes方程的高马赫数极限

Jinkai Ni, Zhipeng Zhang

AI总结 研究临界Besov框架下可压缩Navier-Stokes系统的高马赫数极限,通过参数依赖的低阶估计证明小初始数据下系统的整体适定性,并恢复无压Navier-Stokes系统的全局强解,对d≥3导出定量误差估计。

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30 pages
AI中文摘要

我们在临界Besov框架下研究缩放的可压缩Navier-Stokes系统的高马赫数极限。在缩放的动量方程中,压力力由项\(\varepsilon^2\nabla a^\varepsilon\)表示,其中\(\varepsilon\)是马赫数的倒数;当\(\varepsilon\to0\)时,形式极限系统是可压缩无压Navier-Stokes系统。由于极限模型中缺乏密度耗散以及粘性项产生的高阶耦合,分析变得复杂。对于\(d\geq2\),我们证明了小初始数据下缩放系统的整体适定性,并获得了关于\(\varepsilon\)一致的估计。一个关键因素是参数依赖的低阶估计\(\varepsilon a^\varepsilon\),它补偿了密度方程的纯输运性质,使得一致界得以闭合。基于这些估计,我们证明了高马赫数极限,并恢复了无压Navier-Stokes系统的全局强解。对于\(d\geq3\),我们进一步推导了缩放解与无压极限解之间的定量误差估计。更精确地,在每个固定的有限时间区间上,如果初始差异为\(\mathcal{O}(\varepsilon)\)量级,那么相应的低阶临界Besov误差具有相同的阶,从而给出了无压极限的定量证明。

英文摘要

We investigate the high Mach number limit for the scaled compressible Navier--Stokes system in the critical Besov framework. In the scaled momentum equation, the pressure force is represented by the term \(\varepsilon^2\nabla a^\varepsilon\), where $\varepsilon$ is the inverse Mach number; as \(\varepsilon\to0\), the formal limiting system is the compressible pressureless Navier--Stokes system. The analysis is complicated by the absence of density dissipation in the limiting model and by the highest-order coupling created by the viscous terms. For \(d\geq2\), we prove the global well-posedness of the scaled system for small initial data and obtain estimates that are uniform with respect to $\varepsilon$. A crucial ingredient is a parameter-dependent lower-order estimate for \(\varepsilon a^\varepsilon\), which compensates for the purely transport nature of the density equation and allows the uniform bounds to be closed. Based on these estimates, we justify the high Mach number limit and recover a global strong solution to the pressureless Navier--Stokes system. For \(d\geq3\), we further derive quantitative error estimates between the scaled solutions and the pressureless limiting solution. More precisely, on each fixed finite time interval, if the initial discrepancy is of order \(\mathcal{O}(\varepsilon)\), then the corresponding lower-order critical Besov error satisfies the same rate, which yields a quantitative justification of the pressureless limit.

2606.09807 2026-06-09 math.CV math.CA 新提交

Pathological function spaces and an unsolved Analysis I problem

病态函数空间与一个未解决的数学分析 I 问题

Thomas Ransford

AI总结 本文研究单位圆盘上的一类病态全纯函数空间,其中存在函数虽可用多项式逼近,但无法用其泰勒级数部分和逼近,并由此引出一个仍未解决的级数收敛问题。

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18 pages
AI中文摘要

标题中的空间是单位圆盘上的全纯函数空间,包含一个具有奇特性质的函数:尽管它可以在范数下被多项式逼近,但无法被其自身泰勒级数的部分和逼近,也无法被这些部分和的任何线性组合逼近。寻找这类空间的具体例子引出了一个关于收敛级数的初等问题,该问题至今仍未解决。

英文摘要

The spaces in the title are holomorphic function spaces on the unit disk containing a function with the bizarre property that, although it can be approximated in norm by polynomials, it cannot be approximated by the partial sums of its own Taylor series, nor by any linear combinations thereof. The search for concrete examples of such spaces leads to an elementary problem about convergent series that is still unsolved.

2606.09801 2026-06-09 math.CO cs.DM 新提交

On the generalized Turán number of complete bipartite graphs

关于完全二部图的广义Turán数

Oliver Janzer, Sean Longbrake, Liana Yepremyan

AI总结 本文证明了当s∈{2,3}且s<a≤b且t足够大时,ex(n,K_{a,b},K_{s,t})=Θ(n^s),并证明了对于任意含边图F,存在无穷多个实数r使得ex(n,F,H)=Θ(n^r)对某个H成立。

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17 pages
AI中文摘要

对于图$F$和$H$,广义Turán数$\mathrm{ex}(n,F,H)$表示在$n$个顶点且不含$H$的图中$F$的最大拷贝数。我们证明,如果$s\in \{2,3\}$,$s< a\leq b$且$t$足够大,则$\mathrm{ex}(n,K_{a,b},K_{s,t})=Θ(n^s)$。该结果中$s=2$、$a=b=3$的情形回答了Spiro的一个问题。\n证明Spiro的另一个猜想,我们证明对于每个至少有一条边的图$F$,存在无穷多个实数$r$使得$\mathrm{ex}(n,F,H)=Θ(n^r)$对某个图$H$成立。

英文摘要

For graphs $F$ and $H$, the generalized Turán number $\mathrm{ex}(n,F,H)$ denotes the maximum number of copies of $F$ in an $H$-free graph on $n$ vertices. We prove that if $s\in \{2,3\}$, $s< a\leq b$ and $t$ is sufficiently large, then $\mathrm{ex}(n,K_{a,b},K_{s,t})=Θ(n^s)$. The $s=2$, $a=b=3$ case of this result answers a question of Spiro. Proving another conjecture of Spiro, we show that for every graph $F$ with at least one edge, there exist infinitely many real numbers $r$ such that $\mathrm{ex}(n,F,H)=Θ(n^r)$ holds for some graph $H$.

2606.09796 2026-06-09 math.CT 新提交

Actions, semidirect products and crossed semimodules in the category of small categories with a fixed set of objects

固定对象集的小范畴范畴中的作用、半直积和交叉半模

Stefano Ambra

AI总结 将幺半群的作用和半直积推广到以对象集为纤维的范畴纤维上,证明Schreier点与作用之间的伴随在幺半群情形下等价,并建立Schreier内范畴与交叉半模之间的伴随。

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AI中文摘要

我们将幺半群的作用和半直积的经典概念推广到纤维化 $\mathcal{O}\colon\mathbf{Cat}\rightarrow\mathbf{Set}$ 的纤维上,其中 $\mathcal{O}$ 将小范畴 $\mathbb{X}$ 映射到其对象集 $X_0=ob(\mathbb{X})$。我们证明了幺半群 $Y$ 的幺半群作用与 $Y$ 上的Schreier分裂扩张之间的等价性(该等价性众所周知地推广了群的作用与分裂扩张之间的等价性)是纤维 $\mathcal{O}^{-1}(B)$ 中Schreier点与作用之间的更广泛伴随的一个实例。这个伴随当且仅当 $B=1$(即对于幺半群范畴 $\mathbf{Mon}$)时是等价。类似地,我们证明了在纤维 $\mathcal{O}^{-1}(B)$ 中,Schreier内范畴与 $\mathcal{O}^{-1}(B)$ 中的交叉半模范畴之间存在一个伴随(在幺半群情形下,该伴随由Patchkoria得到已知等价)。后者是通过将 $\mathbf{Mon}$ 中的交叉半模概念翻译到 $\mathcal{O}^{-1}(B)$ 中定义的。最后,我们证明,通过适当定义交叉模,最后一个伴随在 $\mathcal{O}$ 的纤维中给出了交叉模与Schreier内群胚之间的等价。

英文摘要

We generalize to the fibres of the fibration $\mathcal{O}\colon\mathbf{Cat}\rightarrow\mathbf{Set},$ defined by mapping a small category $\mathbb{X}$ to its set of objects $X_0=ob(\mathbb{X}),$ the classical notions of action and semidirect product of monoids. We prove that the equivalence between monoid actions of a monoid $Y$ and Schreier split extensions on $Y,$ which is well known to generalize the equivalence between actions and split extensions for groups, is an instance of a broader adjunction between Schreier points and actions in the fibres $\mathcal{O}^{-1}(B).$ This adjunction is an equivalence if and only if $B=1,$ i.e., for the category $\mathbf{Mon}$ of monoids. Similarly, we prove that there is an adjunction (which, in the case of monoids, results in a known equivalence due to Patchkoria) between Schreier internal categories in the fibres $\mathcal{O}^{-1}(B)$ and the category of crossed semimodules in $\mathcal{O}^{-1}(B).$ The latter are defined by translating in $\mathcal{O}^{-1}(B)$ the notion of crossed semimodule in $\mathbf{Mon}.$ Eventually, we prove that, by defining crossed modules appropriately, this last adjunction yields an equivalence between crossed modules and Schreier internal groupoids in the fibres of $\mathcal{O}.$

2606.09795 2026-06-09 math.CO cs.IT cs.NA hep-th math-ph math.IT math.MP math.NA 新提交

Finite-n Estimate of Dedekind Numbers by Layer-Ratio Monte Carlo

通过层比蒙特卡洛方法对戴德金数的有限n估计

Tian-Shun Chen, Hao Feng, Haozhe Wang, Kilar Zhang

AI总结 将戴德金数问题转化为布尔格理想格的层比重建问题,利用可逆固定层马尔可夫链估计层比,从而估计戴德金数M(n),并发现n=9时中心层附近存在双肩特征。

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27 pages, 6 figures, 7 tables
AI中文摘要

戴德金问题计数单调布尔函数,等价于布尔格的下集。我们将此枚举重新表述为秩理想格的惠特尼数的有限层比重建问题。精确的相邻层双重计数通过可加元素数和可移除元素数的局部平均值表达每个层比。可逆固定层马尔可夫链估计这些平均值,从而估计戴德金数M(n)。在M(8)和M(9)上的回测校准了固定协议下的种子级变异性,并测量了观察到的蒙特卡洛预算缩放。所得估计探测了理想格的惠特尼数序列。尽管这些行先前被经验描述为单峰的,但高精度n=9估计在中心秩附近有一个浅的双肩特征,与经验描述相反;n=11和n=13中心窗口估计显示出更大对比度的类似模式。M(10)的协议估计为\\[ \widehat M(10)=(8.9360\pm0.0010)\times 10^{78}, \\] 其中显示的不确定性是生产预算下跨n缩放定律的基于预算的预测尺度。

英文摘要

Dedekind's problem counts monotone Boolean functions, equivalently downsets of a Boolean lattice. We recast this enumeration as a finite layer-ratio reconstruction problem for the Whitney numbers of the ranked ideal lattice. An exact adjacent-layer double count expresses each layer ratio through local averages of the number of addable elements and the number of removable elements. Reversible fixed-layer Markov chains estimate these averages and hence estimate the Dedekind number M(n). Backtests at M(8) and M(9) calibrate seed-level variability under the fixed protocol and measure the observed Monte Carlo budget scaling. The resulting estimate probes the Whitney-number sequence of the ideal lattice. Although these rows have previously been described empirically as unimodal, the high-precision n=9 estimate has a shallow two-shoulder feature around the central rank, contrary to that empirical description; n=11 and n=13 center-window estimates show a larger-contrast analogous pattern. The protocol estimate for M(10) is \[ \widehat M(10)=(8.9360\pm0.0010)\times 10^{78}, \] where the displayed uncertainty is the budget-based forecast scale from the cross-n scaling law under the production budget.

2606.09785 2026-06-09 math.CO cs.DM 新提交

Biclique decompositions from Welzl orders

从Welzl序的二部团分解

Jean Cardinal, Rose McCarty, Yelena Yuditsky

AI总结 研究图边划分为完全二部子图(二部团分解)的问题,利用Welzl序证明低邻域复杂度图存在小尺寸分解,并推广到Zarankiewicz问题、矩阵乘法、量子电路复杂度和最短路径算法。

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AI中文摘要

图的二部团分解是将其边划分为完全二部子图。我们考虑顶点可排序的图,使得每个顶点的邻域是亚线性个区间的并集。我们观察到这些图允许以紧凑的二部团分解形式表示,其中分解的大小以其二部团的顶点数之和来衡量。结合这一结果与Welzl在1988年证明的低邻域复杂度图存在合适顶点排序的结论,我们恢复并扩展了几个已知结果,达到对数因子。这些结果包括Zarankiewicz问题、矩阵乘法、量子电路复杂度以及“结构良好”实例中最短路径算法的上界。

英文摘要

A biclique decomposition of a graph is a partition of its edges into complete bipartite subgraphs. We consider graphs whose vertices can be ordered such that the neighborhood of every vertex is the union of a sublinear number of intervals. We observe that these graphs admit compact representations in the form of biclique decompositions of small size. Here, the size of a decomposition is measured as the sum of the number of vertices of its bicliques. Combining this result with the existence of suitable vertex orderings for graphs of low neighborhood complexity, as proven by Welzl in 1988, we recover and extend several known results up to logarithmic factors. These results include upper bounds on the Zarankiewicz problem, matrix multiplication, quantum circuit complexity, and shortest path algorithms in ``well-structured'' instances.

2606.09784 2026-06-09 math.OC math.PR 新提交

Mean field games with option to buy information

具有购买信息选项的平均场博弈

Bernardo D'Auria, Markus Fischer

AI总结 研究连续时间有限时域平均场博弈,其中代表性玩家的目标函数依赖于隐藏状态,玩家可选择付费观察该状态,通过连接最优控制与自由停止模型给出解的表征和显式示例。

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AI中文摘要

我们引入了一类连续时间有限时域平均场博弈,其中代表性玩家的目标函数除了依赖于位置、控制和总体分布外,还依赖于一个隐藏状态。在作用于位置动态的同时,代理人有选项付费观察隐藏状态。我们将模型的原始公式与具有自由停止的最优控制平均场模型联系起来,刻画解的特征,并给出一个简单可显式求解的例子。对于一类具有兼容信息结构的$N$人博弈,我们证明可以从极限模型的解出发构造近似纳什均衡。

英文摘要

We introduce a class of continuous time finite horizon mean field games where the objective function of the representative player depends on a hidden state, in addition to position, control, and the population distribution. While acting on the position dynamics, the agent has the option to pay for seeing the hidden state. We connect the original formulation of our model with a mean field model of optimal control with discretionary stopping, characterize solutions, and give a simple explicitly solvable example. For a class of $N$-player games with compatible information structure, we show that approximate Nash equilibria can be constructed starting from a solution to the limit model.

2606.09783 2026-06-09 math.FA 新提交

On some geometrization of compact metric spaces: A solution to the Banach-Ulam conjecture

关于紧度量空间的某种几何化:Banach-Ulam 猜想的一个解

Grzegorz Tomkowicz

AI总结 提出基于Banach和Mycielski思想的紧度量空间几何化方法,证明了Banach-Ulam猜想:每个紧度量空间存在有限可加、合同不变的测度,并解决了Talagrand问题。

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AI中文摘要

我们提出了一种基于S. Banach和J. Mycielski思想的紧度量空间几何化方法。然后证明了1935年S. Banach和S. Ulam的如下猜想:在每个紧度量空间中,存在一个有限可加的概率测度,在合同变换下不变。此外,我们的技术使我们能够解决M. Talagrand的一个问题,该问题与Marczewski问题和Banach-Tarski悖论有关,其中碎片具有Baire性质。我们还给出了关于Hilbert立方体中乘积Lebesgue测度的Ulam猜想的一个非常简单的证明,并用我们的几何化语言解释了关于合同不变Borel测度的现有结果。

英文摘要

We propose a geometrization of compact metric spaces that is based on ideas of S. Banach and J. Mycielski. Then we prove the following conjecture of S. Banach and S. Ulam from 1935: in every compact metric space there exists a finitely additive probability measure, invariant under congruences. Moreover, our techniques allow us to solve a problem of M. Talagrand related to the Marczewski problem and the Banach-Tarski paradox with pieces having the property of Baire. We give also a very simple proof of the conjecture of Ulam about the product Lebesgue measure in the Hilbert cube and explain the existing results about congruence-invariant Borel measures in the language of our geometrization.

2606.09775 2026-06-09 math.AP math.SP 新提交

Linear Stability of the Lamb-Chaplygin Dipole

Lamb-Chaplygin偶极子的线性稳定性

Francesco Pio Numero, Paolo Ventura

AI总结 通过哈密顿结构及对称性,识别了二维欧拉方程中Lamb-Chaplygin偶极子线性不稳定性的两种机制,并完全分类了线性化算子的谱和若尔当链。

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16 pages, 1 figure
AI中文摘要

我们描述了Lamb-Chaplygin偶极子(二维欧拉方程的一个经典行波解)附近的线性化动力学。利用系统的哈密顿结构及其对称性,我们识别了所有可能的线性不稳定性来源。对于$L^1\cap L^p$($p>2$)中的一般扰动,增长只能通过两种显式机制发生:(i)偶极子核心上的非零环量,以及(ii)沿与特征值$0$相关的广义特征向量的非平凡分量。特别地,我们完全分类了与线性动力学相关的算子的谱和若尔当链。这两种机制暗示了非线性动力学可能沿着对称性生成的行波偶极子族漂移,而不会远离该族。

英文摘要

We describe the linearized dynamics near the Lamb-Chaplygin dipole, a classical traveling solution of the two-dimensional Euler equations. Exploiting the Hamiltonian structure of the system together with its symmetries, we identify all possible sources of linear instability. For general perturbations in $L^1\cap L^p$, $p>2$, growth can occur only through two explicit mechanisms triggered by: {\rm (i)} a nonzero circulation on the core of the dipole, and {\rm (ii)} a nontrivial component along the generalized eigenvectors associated with the eigenvalue $0$. In particular, we completely classify the spectrum and the Jordan chains of the operator associated with the linear dynamics. Both mechanisms hint for a nonlinear dynamics that may drift along the symmetry-generated family of traveling dipoles without moving away from it.

2606.09769 2026-06-09 hep-th math-ph math.MP 新提交

All-multiplicity monodromy and KLT relations for AdS string integrals

全多重单值性与AdS弦积分KLT关系

Maria Nocchi, Rodrigo Schmidt Pitombo, Aurélie Strömholm Sangaré, Yi-Xiao Tao

AI总结 提出全多重AdS树级弦振幅构建块,通过多变量多重多对数及其单值类比修饰平面积分,推导开弦单值性关系与闭弦KLT分解,将低点平面对偶非对易AdS提升推广至一般n点运动学。

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AI中文摘要

我们提出并研究了AdS中树级弦振幅的全多重构建块。这些是世界sheet积分,通过分别用多变量多重多对数及其单值类比修饰相应的平面积分(圆盘和球面)得到。我们推导了开弦构建块的单值性关系以及闭弦构建块的KLT分解。这将低点平面对偶结构的非对易AdS提升推广到一般的$n$点运动学。

英文摘要

We propose and study all-multiplicity building blocks for tree-level string amplitudes in AdS. These are worldsheet integrals obtained by dressing the corresponding flat-space disc and sphere integrals with multivariable multiple polylogarithms and their single-valued analogues, respectively. We derive monodromy relations for the open-string building blocks and a KLT factorisation for their closed-string counterparts. This extends the non-commutative AdS uplift of lower-point flat-space structures to general $n$-point kinematics.

2606.09761 2026-06-09 math.LO math.CO 新提交

$\mathbb Z$-Ramsey ultrafilters

$\mathbb Z$-Ramsey 超滤子

José Antonio Corona-García, David José Fernández-Bretón, Ulises Ariet Ramos-García

AI总结 研究Z-Ramsey超滤子,证明其不存在的一致性,并揭示其选择性性质,同时构造反例解决Petrenko和Protasov的开放问题。

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15 pages
AI中文摘要

我们研究 $\mathbb{Z}$-Ramsey 超滤子,即包含 Ramsey 定理每个平移不变实例的见证者的超滤子。我们证明不存在 $\mathbb Z$-Ramsey 超滤子是一致的。我们还证明每个 $(\mathbb{Z},3)$-Ramsey 超滤子以及每个 $\mathbb{Z}$-Ramsey P-点都是选择性的。此外,我们展示了一个泛型扩张——使用形如 \\(\mathcal{P}(\mathbb{Z})/\mathcal{I}\\) 的商代数,其中 \\(\mathcal{I}\\) 是某些 \\(F_{\sigma}\\)-理想——该扩张包含不是 \\(\mathbb{Z}\\)-Ramsey 超滤子的 P-点,从而解决了 Petrenko 和 Protasov 提出的开放问题。

英文摘要

We study $\mathbb{Z}$-Ramsey ultrafilters, ultrafilters containing witnesses to every shift-invariant instance of Ramsey's theorem. We prove that it is consistent that there are no $\mathbb Z$-Ramsey ultrafilters. We also prove that every $(\mathbb{Z},3)$-Ramsey ultrafilter, as well as every $\mathbb{Z}$-Ramsey P-point, is selective. Further, we exhibit a generic extension -- using quotient algebras of the form \(\mathcal{P}(\mathbb{Z})/\mathcal{I}\) for certain \(F_{σ}\)-ideals -- that contains P-points that are not \(\mathbb{Z}\)-Ramsey ultrafilters, thereby addressing open questions raised by Petrenko and Protasov.

2606.09747 2026-06-09 math.AT math.CT 新提交

Homotopy theories via the magnitude-path spectral sequence

通过量级-路径谱序列的同伦理论

Muriel Livernet, Emily Roff, Sarah Whitehouse

AI总结 引入基于量级-路径谱序列的广义度量空间同伦理论族,定义r-拟同构并证明每页满足Eilenberg-Steenrod公理的度量类比,建立Brown范畴结构以计算同伦余极限。

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34 pages, 4 figures
AI中文摘要

我们通过量级-路径谱序列(MPSS)引入了一族针对具有自然数距离的广义度量空间的同伦理论。MPSS的第一页称为量级同调;第二页称为双分次路径同调,其顶行包含GLMY路径同调。对于每个自然数r,我们定义了一类度量空间映射,称为r-拟同构:这些映射在MPSS的第r页上诱导拟同构。我们证明谱序列的每一页满足Eilenberg-Steenrod公理的适当度量类比。特别地,我们引入了r-上纤维化的概念,并证明了关于r-上纤维化的第r页的Mayer-Vietoris定理。我们在广义度量空间上建立了一族Brown范畴结构,使得我们能够显式计算同伦余极限。我们应用此来描述n维的r-悬垂和r-球面,并计算它们的谱序列。最后,我们证明对于r=1,整个理论限制到有向图上。

英文摘要

We introduce a family of homotopy theories for generalized metric spaces with natural number distances, via the magnitude-path spectral sequence (MPSS). The first page of the MPSS is known as magnitude homology; the second page is known as bigraded path homology, and contains GLMY path homology as its top row. For each natural number r, we define a class of maps of metric spaces called r-quasi-isomorphisms: those maps that induce a quasi-isomorphism at page r of the MPSS. We show that every page of the spectral sequence satisfies a suitable metric analogue of each of the Eilenberg-Steenrod axioms. In particular, we introduce the notion of r-cofibration and prove a Mayer-Vietoris theorem for page r with respect to r-cofibrations. We establish a family of Brown category structures on generalized metric spaces which allow us to explicitly compute homotopy colimits. We apply this to describe r-suspension and r-spheres of dimension n, and compute their spectral sequences. Finally we prove that for r = 1 the entire theory restricts to directed graphs.

2606.09743 2026-06-09 math.DS math.CA 新提交

Fourier transform of nonlinear images of self-similar measures: qualitative aspects

自相似测度非线性像的傅里叶变换:定性方面

Amlan Banaji, Han Yu

AI总结 研究在足够非线性的实解析映射下,自相似测度像的傅里叶多项式衰减,关键步骤包括建立自相似测度的均匀Lojasiewicz型不等式并利用测度傅里叶变换在频率小集外的衰减。

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45 pages
AI中文摘要

本文的目标是建立$\mathbb{R}^k$上自相似测度$\mu$在足够非线性的实解析映射$f \colon \mathbb{R}^k \to \mathbb{R}^d$下的像的多项式傅里叶衰减。例如,我们证明如果$f$在$\mathbb{R}^k$上解析,其图像不位于$\mathbb{R}^{k+d}$中的仿射超平面内,且$\mu$不支撑在$\mathbb{R}^k$中的仿射超平面内,那么像测度具有多项式傅里叶衰减。证明的关键步骤包括建立自相似测度的均匀Lojasiewicz型不等式,并利用$\mu$的傅里叶变换在非常小的频率例外集之外的衰减。作为我们结果的应用,我们证明了$\mathbb{C}$上一大类复解析迭代函数系统(非自相似但通过解析映射共轭于线性迭代函数系统)的自共形测度的多项式傅里叶衰减。

英文摘要

The goal of this paper is to establish polynomial Fourier decay for images of self-similar measures $μ$ on $\mathbb{R}^k$ under sufficiently nonlinear real-analytic maps $f \colon \mathbb{R}^k \to \mathbb{R}^d$. For example, we prove that if $f$ is analytic on $\mathbb{R}^k$, its graph does not lie in an affine hyperplane in $\mathbb{R}^{k+d}$, and $μ$ is not supported in an affine hyperplane in $\mathbb{R}^k$, then the image measure has polynomial Fourier decay. Key steps in the proof include establishing a uniform Lojasiewicz-type inequality for self-similar measures, and using the decay of the Fourier transform of $μ$ outside a very small exceptional set of frequencies. As an application of our results, we prove polynomial Fourier decay for self-conformal measures on $\mathbb{C}$ for a large class of complex analytic IFSs which are not self-similar but are conjugate to a linear IFS via an analytic map.

2606.09742 2026-06-09 math.CO 新提交

Towards the Lovász conjecture via sublinear expanders

走向通过次线性展开图的Lovász猜想

Matija Bucić, Micha Christoph, Alexey Pokrovskiy, Raphael Steiner

AI总结 通过结合次线性展开图中的路径嵌入技术、几乎正则图的次线性展开图分解等组合方法,证明了每个n阶连通顶点传递图包含长度至少为n^{2/3-o(1)}的圈,改进了之前的最佳下界。

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20 pages
AI中文摘要

Lovász著名的哈密顿性猜想(1969)指出,每个连通顶点传递图都有哈密顿路径。该猜想的更强版本(常归功于Thomassen,1978)指出,每个足够大的此类图甚至都有哈密顿圈。尽管过去几十年中,这些猜想在组合和代数领域引起了大量关注,但在40多年里,连通顶点传递图中圈(路径)最大长度的最佳已知下界仍为$Ω(\sqrt{n})$(Babai,1979)。最近一系列工作逐步改进了该下界的指数。本文改进了Norin等人(2025)先前的最优下界$Ω(n^{9/14})$,证明了每个n阶连通顶点传递图包含长度至少为$n^{2/3-o(1)}$的圈。这达到了先前工作中几种现有方法的自然屏障。我们的证明结合了次线性展开图中路径的近期嵌入技术、几乎正则图的次线性展开图分解以及若干额外的组合思想。

英文摘要

Lovász' famous Hamiltonicity conjecture (1969) states that every connected vertex-transitive graph has a Hamiltonian path. A stronger version of the conjecture, often attributed to Thomassen (1978), states that every sufficiently large such graph even has a Hamiltonian cycle. Despite the great amount of attention these conjectures have attracted over the past decades both in the combinatorial and algebraic communities, for more than 40 years the best known lower bound for the maximum length of a cycle (path) in a connected vertex-transitive graph of order $n$ remained of the form $Ω(\sqrt{n})$, due to Babai (1979). A series of recent works has successively improved the exponent in this lower bound further. In this paper, improving the previous state-of-the-art bound $Ω(n^{9/14})$ due to Norin et al.~(2025), we prove that every connected vertex-transitive graph of order $n$ contains a cycle of length at least $n^{2/3-o(1)}$. This hits a natural barrier for several existing approaches from previous work. Our proofs combine recent embedding techniques for paths in sublinear expanders, sublinear expander decompositions of almost-regular graphs, and several additional combinatorial ideas.

2606.09739 2026-06-09 math.NT 新提交

Power Integral Bases in Polynomial Compositions

多项式复合中的幂积分基

Aakash Choudhary, Supriya Pisolkar, Prabhakar Yadav

AI总结 研究形如 (f∘g)(x) 的复合多项式的单源性,给出参数条件使 {1,θ,…,θ^{mn-1}} 构成数域的积分基,并给出此类单生成多项式的计数下界。

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AI中文摘要

本文研究了一类特殊复合多项式的单源性,其形式为 (f∘g)(x) = (x^m + c)^n + a(x^m + c)^{n-1} + d(x^m + c)^{n-2} + b,其中 f(x) = x^n + a x^{n-1} + d x^{n-2} + b ∈ ℤ[x] 满足 a^2 = 4d,且 g(x) = x^m + c ∈ ℤ[x]。假设 (f∘g)(x) 在 ℚ 上不可约,我们得到了参数 a, b, c, d, m, n 使得该多项式为单生成的充要条件。这些条件有助于确定集合 {1, θ, …, θ^{mn-1}} 何时构成数域 ℚ(θ) 的积分基,其中 θ 是 (f∘g)(x) 的一个根。我们还给出了此类单生成多项式计数的下界。此外,我们研究了某些相关微分方程解的行为,并作为主要结果的应用,给出了一类判别式非无平方因子的多项式。

英文摘要

In this paper, we study the monogeneity of a special class of composed polynomials of the form $ (f \circ g)(x) = (x^m + c)^n + a(x^m + c)^{n-1} + d(x^m + c)^{n-2} + b,$ where \( f(x) = x^n + a x^{n-1} + d x^{n-2} + b \in \mathbb{Z}[x] \) satisfies \( a^2 = 4d \) and \( g(x) = x^m + c \in \mathbb{Z}[x] \). Assuming that \( (f \circ g)(x) \) is irreducible over \( \mathbb{Q} \), we obtain necessary and sufficient conditions on the parameters \( a, b, c, d, m, n \) for the polynomial to be monogenic. These conditions help to identify when the set \( \{1, θ, \dots, θ^{mn-1}\} \) forms an integral basis of the number field \( \mathbb{Q}(θ) \), where \( θ\) is a root of \( (f \circ g)(x) \). We also provide lower bound for the counting of such monogenic polynomials. Furthermore, we study the behaviour of solutions to certain related differential equations and present a class of polynomials with non-square-free discriminants as an application of the main results.

2606.09737 2026-06-09 math.ST stat.TH 新提交

Online change point detection under heavy-tailedness and contamination

重尾与污染下的在线变点检测

Edwin Yiu Nam Tang, Yudong Chen, Mengchu Li, Yi Yu

AI总结 针对动态Huber污染模型,提出在线鲁棒均值变点检测方法,在单变量中划分参数空间实现最优检测延迟,多变量中设计鲁棒均值检验程序,首次同时处理Huber污染和重尾性。

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AI中文摘要

我们研究了在动态Huber污染模型下的在线鲁棒均值变点检测问题,该模型具有任意污染分布和具有指数或多项式衰减尾部的内点分布。这种鲁棒性框架在变点文献中首次被系统研究。对于单变量数据,我们通过根据真实变点位置、信号大小和污染水平将参数空间划分为四个区域来刻画检测延迟。高效的检测程序伴随匹配的下界,直到多对数因子。对于多变量设置,我们设计了一个高效的鲁棒均值检验程序,并将其应用于鲁棒在线变点问题。该鲁棒均值检验程序的理论分析是首次同时处理Huber污染和重尾性,因此具有独立的研究价值。进行了大量的数值实验以支持我们的理论发现。

英文摘要

We study an online version of the robust mean change point detection problem under a dynamic Huber contamination model with arbitrary contamination distribution and inlier distribution possessing exponentially- or polynomially-decaying tails. This robustness framework is systematically studied for the first time in the change point literature. For univariate data, we characterise the detection delay by partitioning the parameter space into four regimes, in terms of the true change location, signal size and contamination level. Efficient detection procedures are accompanied by matching lower bounds, up to poly-logarithmic factors. For the multivariate setting, we devise an efficient robust mean testing procedure and apply this to the robust online change point problem. The theoretical analysis of the robust mean testing procedure is the first in dealing with both Huber contamination and heavy-tailedness, and is thus of independent interest. Extensive numerical experiments are conducted to support our theoretical findings.

2606.09736 2026-06-09 math.CO cs.DM 新提交

Almost-perfect packings and Tuza's conjecture in the random geometric graph

随机几何图中的几乎完美打包与Tuza猜想

Patrick Bennett, Ryan Cushman, Andrzej Dudek, Xavier Pérez-Giménez

AI总结 研究随机几何图中Tuza猜想成立的条件,并证明对于一大类密度该猜想成立;同时研究用固定图F的边不交副本覆盖几乎所有边的问题,对无限族F证明了几乎完美打包的存在性。

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26 pages
AI中文摘要

图$G$的三角形打包数$ν(G)$是$G$中边不交三角形的最大数量。Tuza猜想:在任何图$G$中,存在一个大小至多为$2ν(G)$的边集,与$G$中每个三角形相交。我们证明,对于一大类密度,Tuza猜想在随机几何图中成立。我们还研究了用某个固定图$F$的边不交副本覆盖随机几何图几乎所有边的问题。特别地,我们证明了对于无限族$F$存在几乎完美打包,并给出了一些否定结果。

英文摘要

The triangle packing number $ν(G)$ of a graph $G$ is the maximum size of a set of edge-disjoint triangles in $G$. Tuza conjectured that in any graph $G$ there exists a set of at most $2ν(G)$ edges intersecting every triangle in $G$. We show that Tuza's conjecture holds in the random geometric graph for a large range of densities. We also study the problem of covering almost all edges of the random geometric graph with edge-disjoint copies of some fixed graph $F$. In particular, we show the existence of almost-perfect packings for an infinite family of $F$, and state some negative results as well.

2606.09733 2026-06-09 math.CO 新提交

On saturation problems involving clique number and matching number

关于涉及团数和匹配数的饱和问题

Zian Chen, Guorong Gao, Jianfeng Hou, Yue Ma

AI总结 本文研究固定匹配数的K_r饱和图的最小边数,给出了下界并刻画了极图。

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11page
AI中文摘要

对于一个团 $K_r$,如果图不包含 $K_r$ 作为子图,但添加其补图中的任意一条边都会产生一个 $K_r$,则该图是 $K_r$-饱和的。Erdős-Hajnal-Moon 和 Zykov 的一个经典结果表明,$n$ 个顶点的 $K_r$-饱和图的边数至少为 $(r-2)n-\binom{r-1}{2}$。本文关注具有固定匹配数的 $K_r$-饱和图的边数。设 $G$ 是一个 $n$ 个顶点的 $K_r$-饱和图,匹配数为 $ν(G) = s$。对于足够大的 $n$,我们证明边数 \begin{equation*} e(G)\geq \left\{\begin{array}{cl}{(r-1)n-\frac{r}{2}(r-1)-1,}&{\quad\mathrm{if}~s=r-1;}\{(r-1)n + (s-r)^2 - \frac{1}{2}(r+2)(r-3) - 5,}&{\quad\mathrm{if}~s>r-1.}\end{array}\right. \end{equation*} 此外,我们完全刻画了达到等式的图。

英文摘要

For a clique $K_r$, a graph is $K_r$-saturated if it contains no copy of $K_r$ and the addition of any edge from its complement creates a $K_r$. A classical result of Erdős-Hajnal-Moon and Zykov shows that the number of edges of an $n$-vertex $K_r$-saturated graph is at least $(r-2)n-\binom{r-1}{2}$. In this paper, we focus on the number of edges of the $K_r$-saturated graphs with a fixed matching number. Let $G$ be an $n$-vertex $K_r$-saturated graph with matching number $ν(G) = s$. For sufficiently large $n$, we prove that the number of edges \begin{equation*} e(G)\geq \left\{\begin{array}{cl}{(r-1)n-\frac{r}{2}(r-1)-1,}&{\quad\mathrm{if}~s=r-1;}\\{(r-1)n + (s-r)^2 - \frac{1}{2}(r+2)(r-3) - 5,}&{\quad\mathrm{if}~s>r-1.}\\\end{array}\right. \end{equation*} Moreover, we completely characterize the graphs attaining the equality.

2606.09702 2026-06-09 math.GR math.GT 新提交

On profinite rigidity, Grothendieck pairs, and the second homology of some $3$-orbifold groups

关于profinite刚性、Grothendieck对以及某些$3$-orbifold群的第二同调

Carl-Fredrik Nyberg-Brodda

AI总结 本文开发了一种有效计算双曲有理同调$3$-球面orbifold群第二同调群的方法,并应用于Weeks流形及其相关格点,证明了这些格点的绝对profinite刚性,并构造了Grothendieck对。

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Comments welcome!
AI中文摘要

第二同调群在$3$-流形群的profinite刚性研究中至关重要。尽管一般性和深刻的结果表明,余紧双曲$3$-orbifold群的整同调在原则上是可计算的,但由此产生的算法并不实用。我们针对作为双曲有理同调$3$-球面基本群的有限扩张的orbifold群,开发了一种计算$H_2$的有效方法。作为一个特例,这给出了介于$π_1(\mathcal{W})$与其在$\mathrm{PSL}_2(\mathbb C)$中的正规化子之间的所有余紧格点的第二同调群的显式计算,其中$\mathcal{W}$是Weeks流形。我们还证明了这些格点是绝对profinite刚性的,完成了Bridson、McReynolds、Reid和Spitler在此背景下的工作。作为一个特例,我们确定$H_2(Γ_{\mathcal{O}}, \mathbb Z) \cong \mathbb{Z} / 2\mathbb{Z}$,其中$Γ_{\mathcal{O}}$是与$\mathcal{W}$相关的四元数代数的某个极大序$\mathcal{O}$的单位群$Γ_{\mathcal{O}}^1$的正规化子,从而回答了Bridson和Reid的一个问题。尽管这个非零性阻碍了在$Γ_{\mathcal{O}}^1 \times Γ_{\mathcal{O}}^1$中构造Grothendieck对的一种可能,我们利用我们的计算证明了另一个其导出子群为$Γ_{\mathcal{O}}^1$的格点的第二同调为零,从而通过Bridson和Reid的一个定理在该直积中产生了Grothendieck对。最后,为了展示这些技术的普适性,我们还计算了某些Fibonacci流形$M_n$基本群通过可定向等距的有限扩张的第二同调。

英文摘要

The second homology group is of central importance in the study of profinite rigidity of $3$-manifold groups. Although general and deep results imply that the integral homology of cocompact hyperbolic $3$-orbifold groups is computable in principle, the resulting algorithm is not practical. We develop an effective method for computing $H_2$ in the case of orbifold groups arising as finite extensions of the fundamental group of hyperbolic rational homology $3$-spheres. As a special case, this yields explicit computations of the second homology groups of all cocompact lattices between $π_1(\mathcal{W})$ and its normalizer in $\mathrm{PSL}_2(\mathbb C)$, where $\mathcal{W}$ is the Weeks manifold. We also show that these lattices are absolutely profinitely rigid, completing work by Bridson, McReynolds, Reid & Spitler in this setting. As a special case, we determine that $H_2(Γ_{\mathcal{O}}, \mathbb Z) \cong \mathbb{Z} / 2\mathbb{Z}$, where $Γ_{\mathcal{O}}$ is the normalizer of the group of units $Γ_{\mathcal{O}}^1$ in a choice of maximal order $\mathcal{O}$ of the quaternion algebra associated to $\mathcal{W}$, thereby answering a question of Bridson & Reid. Although this non-vanishing obstructs one possible construction of Grothendieck pairs in $Γ_{\mathcal{O}}^1 \times Γ_{\mathcal{O}}^1$, we use our computations to show the vanishing of the second homology of another lattice whose derived subgroup is $Γ_{\mathcal{O}}^1$, which then yields Grothendieck pairs in this direct product by a theorem of Bridson & Reid. Finally, to showcase the generality of the techniques, we also compute the second homology of some finite extensions by orientable isometries of the fundamental group of some Fibonacci manifolds $M_n$.

2606.09698 2026-06-09 cs.IT cs.SY eess.SY math.IT math.OC 新提交

Optimal Feedback Communication with Information Maximization and Distortion Minimization

信息最大化与失真最小化的最优反馈通信

Aolin Xu

AI总结 研究通过带反馈信道传输实值源的最优方案,提出信息最大化与失真最小化的联合优化条件,并证明后验匹配方案在对称离散信道中同时实现两者最优。

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AI中文摘要

我们研究了通过多次使用带反馈的信道最优地发送实值源的问题。首先,我们陈述了一组充分条件,使得编码器能够实现源与所有信道输出之间的最大互信息。当信道是输入可识别时(这是常见信道模型广泛满足的条件),这组条件也是必要的。更值得注意的是,我们进一步研究了信息最大化-失真最小化问题,其中源与所有信道输出之间的互信息仍需最大化,同时在每一步,基于当前信道输出对源的MMSE估计也需最小化。我们针对具有特定对称性的离散信道(例如$k$元对称信道或$k$元删除信道)推导了该问题的解。我们证明,对于此类信道,著名的后验匹配方案虽然对于单独的信息最大化并非必要,但对于同时实现信息最大化和失真最小化是充分且本质上必要的。这项工作还提供了通过信息最大化来正则化失真最小化反馈通信的新视角,使我们能够找到否则难以处理的最优解。

英文摘要

We study the problem of optimally sending a real-valued source through multiple uses of a channel with feedback. First, we state a set of conditions that are sufficient for an encoder to achieve maximal mutual information between the source and all the channel outputs. This set of conditions are also necessary when the channel is input-identifiable, a condition widely satisfied by common channel models. More notably, we further study the information maximization-distortion minimization problem, where the mutual information between the source and all channel outputs still needs to be maximized, while at each step, the MMSE of estimating the source from the channel outputs so far also needs to be minimized. We derive a solution to this problem for discrete channels with certain symmetries, e.g. $k$-ary symmetric or $k$-ary erasure channels. We show that for such channels the famous posterior matching scheme, while not necessary for information maximization alone, is sufficient and essentially necessary for achieving both information maximization and distortion minimization. This work also provides a new perspective of regularizing distortion-minimizing feedback communication through information maximization, which enables us to find the optimal solution that otherwise would be intractable.

2606.09696 2026-06-09 math.DS 新提交

Isoenergetic degeneracy generically creates meandering invariant tori

等能简并普遍产生蜿蜒不变环面

Vadim Kaloshin, Illya Koval, Yi Pan

AI总结 研究等能简并可积哈密顿系统在一般扰动下产生非图嵌入的蜿蜒不变环面,并证明存在无穷阶嵌套蜿蜒结构。

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14 pages, 11 figures. This is a short version of a full manuscript, which would be uploaded later
AI中文摘要

考虑具有两个自由度的等能简并可积哈密顿系统集合。我们证明,该集合中一般哈密顿量的尖点一般扰动会产生蜿蜒不变环面——即不是图的嵌入拉格朗日环面。此外,指数稠密的扰动子集允许从二阶到无穷阶的所有阶的高阶蜿蜒环面。这些无穷阶蜿蜒具有无尽嵌套结构。

英文摘要

Consider the set of isoenergetically degenerate integrable Hamiltonians with two degrees of freedom. We show that a cusp-generic perturbation of a generic Hamiltonian in this set gives rise to meandering invariant tori - embedded Lagrangian tori which are not graphs. Moreover, an exponentially dense subset of perturbations admits higher order meandering tori, of all orders from two to infinity. These infinite order meanders have an endless nested structure.

2606.09695 2026-06-09 math-ph math.MP 新提交

Engineering classical waves with quantized energy spectra in periodic media

周期介质中具有量化能谱的经典波工程

Arnaud Lazarus, Georgi Gary Rozenman, John W. M. Bush

AI总结 本文展示通过设计线性周期介质,使波传播仅在离散窄通带内允许,从而在经典波系统中实现类似量子力学的能量量化现象。

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AI中文摘要

场量子化是现代物理学的核心特征,支撑着光子的概念,并构成了量子电动力学以及大部分固体理论的基础。通常,经典线性波动方程在不引入额外因素(如特定非线性约束、共振粒子-波耦合或随机背景场)的情况下,无法重现量子系统中出现的量子化。在这里,我们表明,适当设计的线性波动介质可以恢复量子力学中能量量化的基本特征。关键在于定制周期介质,其中波传播被强烈抑制,除了离散的窄通带集合。在这种状态下,驻波解表现出离散的能量和频率谱,类似于量子力学中的情况,尽管底层动力学仍然是线性的。由于所提出机制的普遍性,这些效应可以通过在适当设计的周期介质中使用机械波、电波或电磁波在实验上实现。这项工作为设计能够控制离散波态的超材料开辟了新途径,同时加强了经典波物理与量子波物理之间的概念桥梁。

英文摘要

Field quantization is a central feature of modern physics, that underpins the concept of photons and forms the foundation of quantum electrodynamics as well as much of solid-state theory. Classical linear wave equations are not generally expected to reproduce the quantization arising in quantum systems without introducing additional ingredients such as ad hoc nonlinear constraints, resonant particle-wave couplings or stochastic background fields. Here, we show that appropriately engineered linear wave media can recover fundamental features evocative of energy quantization in quantum mechanics. The key is to tailor periodic media in which wave propagation is strongly suppressed, except over a discrete set of narrow pass bands. In this regime, stationary wave solutions exhibit discrete energy and frequency spectra analogous to those arising in quantum mechanics despite the underlying dynamics remaining linear. Owing to the universality of the proposed mechanism, these effects may be realized experimentally using mechanical, electrical, or electromagnetic waves in appropriately designed periodic media. This work opens new avenues for designing metamaterials that enable control over discrete wave states while strengthening the conceptual bridge between classical and quantum wave physics.

2606.09693 2026-06-09 math.AG math.AC math.NT 新提交

Bertini theorems for Hilbert-Samuel multiplicity over finite fields

有限域上Hilbert-Samuel重数的Bertini定理

Rahul Ajit, Matthew Bertucci

AI总结 针对有限域上的约化等维拟射影概形,证明存在正密度超曲面集使得交点的重数保持。

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Comments are very much welcome!
AI中文摘要

设 $X\subseteq \mathbb{P}^n_{\mathbb{F}_q}$ 是一个约化、等维、拟射影概形。我们证明存在一个正密度的超曲面 $H_f$ 集合,使得对于每个闭点 $P\in X\cap H_f$,有 $\mathrm{ord}_P(f)=1$ 且 $e_P(X\cap H_f)=e_P(X)$。

英文摘要

Let $X\subseteq \mathbb{P}^n_{\mathbb{F}_q}$ be a reduced, equidimensional, quasiprojective scheme. We prove that there exists a positive-density set of hypersurfaces $H_f$ such that for every closed point $P\in X\cap H_f$, one has $\mathrm{ord}_P(f)=1$ and $e_P(X\cap H_f)=e_P(X)$.

2606.09691 2026-06-09 math.PR 新提交

Degenerate Diffusions on Continuum Percolation and Hamilton-Jacobi-Bellman Equations

连续渗流上的退化扩散与Hamilton-Jacobi-Bellman方程

Rodrigo Bazaes, Alexander Mielke, Chiranjib Mukherjee

AI总结 研究在连续渗流簇上的退化受控扩散和Hamilton-Jacobi-Bellman方程,证明扩散永不触及边界并存在唯一全局强解,建立随机控制表示公式,验证布尔模型等具体模型满足假设。

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AI中文摘要

我们研究在真实连续渗流簇上的退化受控扩散和Hamilton-Jacobi-Bellman方程。扩散被限制在无限簇内演化,并根据到不规则随机边界的距离退化。在扩散矩阵的适当正则性和退化假设下,我们证明相应的受控扩散永不触及边界,因此存在唯一的全局强解。利用这一结果,我们建立了在随机簇上、无需边界条件的退化Hamilton-Jacobi-Bellman方程的粘性解的随机控制表示公式。我们进一步验证了本文引入的结构性假设,包括到边界函数的定量可积性及相关退化性,对具体的连续渗流模型(如布尔模型)成立。特别地,尽管扩散永不触及边界,但边界几何通过允许的退化机制仍然是该理论的基本要素。这些结果为真实连续渗流几何上的随机控制和退化偏微分方程建立了一个淬火框架,并确定了扩散的分析结构与底层簇的随机几何之间的联系。它们还为伴随文章[BMM26]中发展的均匀化理论提供了基础框架。

英文摘要

We study degenerate controlled diffusions and Hamilton--Jacobi--Bellman equations posed on genuine continuum percolation clusters. The diffusion is constrained to evolve inside the infinite cluster and degenerates according to the distance to the irregular random boundary. Under suitable regularity and degeneracy assumptions on the diffusion matrix, we prove that the corresponding controlled diffusion never reaches the boundary and therefore admits a unique global strong solution. Using this result, we establish a stochastic control representation formula for viscosity solutions of degenerate Hamilton--Jacobi--Bellman equations posed on the random cluster, without imposing boundary conditions. We further verify that the structural assumptions introduced in this work, including quantitative integrability properties of the distance-to-the-boundary function and the associated degeneracy, hold for concrete continuum percolation models such as the Boolean model. In particular, although the diffusion never reaches the boundary, the boundary geometry remains a fundamental ingredient of the theory through the admissible degeneracy regime. The results establish a quenched framework for stochastic control and degenerate partial differential equations on genuine continuum percolation geometries, and identify a link between the analytic structure of the diffusion and the stochastic geometry of the underlying cluster. They also provide the foundational framework for the homogenization theory developed in the companion article [BMM26].

2606.09689 2026-06-09 math.NA cs.NA 新提交

Low-Rank Acceleration of the Operator Fourier Transform

算子傅里叶变换的低秩加速

Jack Kelley

AI总结 针对二维结构化网格上的亥姆霍兹方程,结合算子傅里叶变换与低秩交叉逼近(Cross-DEIM),将问题分解为薛定谔方程解的伪时间积分,显著降低计算成本。

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AI中文摘要

我们开发了一种数值算法,用于高效求解或近似求解二维结构化网格上的亥姆霍兹方程。利用算子傅里叶变换(OFT)和低秩交叉逼近方案(Cross-DEIM),将问题分解为薛定谔方程解在伪时间上的积分。OFT是求解算子方程(如分数阶拉普拉斯方程或亥姆霍兹方程,当后者写为两个近轴算子的乘积时)的框架。OFT的主要计算成本在于求解薛定谔方程,尤其是在维度或网格分辨率较高时。在本工作中,我们通过使用低秩方法降低了这一成本。当解中存在低秩结构时,这类方法旨在克服维数灾难。我们表明,对于某些类型的问题,这两种方法的结合可以大幅降低计算成本。

英文摘要

We develop a numerical algorithm for the efficient solution or approximation of solutions to the Helmholtz equation on a structured grid in two dimensions. We make use of the Operator Fourier Transform (OFT) and a low-rank cross approximation scheme (Cross-DEIM) to decompose the problem into an integral over a pseudo-time of solutions to the Schrödinger equation. The OFT is a framework for solving operator equations like fractional Laplacian equations or the Helmholtz equation, when the latter is written as a product of two paraxial operators. The main computational cost in the OFT is the solution to the Schrödinger equation, especially when the dimension or mesh resolution is high. In this work, we alleviate this cost by utilizing a low-rank method. Such methods aim to beat the curse of dimensionality when low-rank structures are present in the solution. We show that the combination of these two approaches can have large cost reductions for certain classes of problems.