生成时间: 2026年03月26日 04:58:27

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重点关注论文(完整分析)

1. 一维随机Navier-Stokes-Korteweg方程的全局唯一可解性

Global unique solvability of the 1D stochastic Navier-Stokes-Korteweg equations

作者: L. Pescatore

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24398v1

摘要翻译: 本文证明了一维Navier-Stokes-Korteweg方程在随机乘法噪声驱动下的全局适定性。分析针对一般形式的毛细管系数和粘性系数 $k(ρ)= ρ^β, \, β\in \mathbb{R},\, μ(ρ)=ρ^α, \, α\ge 0,$ 进行,这些系数之间不通过BD关系耦合。我们在强路径解的正则性类中获得了解的全局存在性与唯一性,这些解既是偏微分方程意义下的强解,也是概率意义下的强解。首先,我们利用多层逼近格式和随机紧性论证,对任意 $\alpha$ 和 $\beta$ 建立局部适定性结果。随后,我们应用BD熵方法来控制密度的真空状态,从而能够执行延拓论证。因此,在无真空且满足文献[49]中引入的强强制性条件 $2α-4 \le β\le 2 α-1$ 的范围内获得了全局适定性。作为副产品,我们还涵盖了确定性情形 $\mathbb{F}=0,$ 据我们所知,这在流体力学文献中同样是一个尚未解决的问题。

Comment: 无

链接: http://arxiv.org/abs/2603.24398v1

1. 研究对象和背景

本文研究的是一维Navier-Stokes-Korteweg方程在随机乘性噪声驱动下的全局适定性。该方程组描述了具有表面张力效应的可压缩粘性流体动力学,是经典Navier-Stokes方程的重要推广。系统包含两个未知函数:流体的密度 $\rho(x,t)$ 和速度 $u(x,t)$,它们在周期域 $\mathbb{T}$ 上满足如下耦合方程组。连续性方程描述质量守恒,而动量方程则刻画了流体运动的物理规律,其中压力项 $p(\rho) = \rho^\gamma$($\gamma \geq 1$)描述了等熵流体的状态方程。

该研究的核心难点在于同时考虑粘性效应和毛细管效应。粘性张量 $S(\partial_x u) = \mu(\rho)\partial_x u$ 和Korteweg张量 $K(\rho,\partial_x\rho)$ 分别由幂律形式的系数给出:$\mu(\rho) = \rho^\alpha$($\alpha \geq 0$)和 $k(\rho) = \rho^\beta$($\beta \in \mathbb{R}$)。值得注意的是,这些系数之间不满足经典的Bresch-Desjardins(BD)关系,这使得分析变得更加复杂。Korteweg张量在相变和扩散界面模型中具有重要物理意义,其结构最初由Dunn和Serrin建立,近年来在量子流体动力学等领域得到广泛应用。

论文还引入了随机驱动项 $\rho F(\rho,u)dW$,其中 $W$ 是圆柱维纳过程,$F$ 是满足特定增长条件和正则性假设的函数。这种乘性噪声形式在物理上对应于随机外力,且在真空集 $\{\rho = 0\}$ 上自动消失。

2. 主要定理或主要结果

本文的主要结果建立了随机Navier-Stokes-Korteweg方程的局部和全局适定性,具体包含两个核心定理。

定理2.3(局部适定性):设 $s > 7/2$ 为整数,假设噪声系数 $F_k$ 满足给定的增长条件和正则性假设。对于任意的 $\alpha \geq 0$ 和 $\beta \in \mathbb{R}$,当初始条件满足适当正则性时,系统存在唯一的极大局部强路径解。这里的强路径解指的是在偏微分方程意义下和概率意义下同时为强解的解。

定理2.4(全局适定性):在定理2.3的假设基础上,额外要求满足强 coercivity 条件 $2\alpha-4 \leq \beta \leq 2\alpha-1$ 和无真空条件 $0 \leq \alpha \leq 1/2$ 或 $\beta \leq -2$。当初始条件具有更高正则性(属于特定Sobolev空间)时,局部解可以延拓为全局解。

作为推论,当噪声强度为零(即 $F=0$)时,本文结果同样给出确定性问题在上述参数范围内的全局适定性,这在流体力学文献中此前是未解决的开问题。研究还建立了强路径解的唯一性和爆破准则:解的最大存在时间 $\tau$ 由 $\|\rho\|_{W^{2,\infty}} + \|u\|_{W^{2,\infty}}$ 的爆破决定。

3. 研究方法、关键技术和核心工具

本文采用的方法融合了随机偏微分方程理论和高维流体力学中的先验估计技术,形成了一套系统的研究框架。

多层逼近格式与随机紧性理论:作者首先对系统进行截断处理,设计了包含Galerkin逼近的多层近似方案。通过对非线性项进行适当的光滑化,得到一族近似系统,然后逐一求解。为了从近似解序列收敛到真实解,作者运用了随机紧性论证,基于Skorokhod表示定理处理紧性问题和收敛性分析。

路径唯一性与Gyongy-Krylov方法:近似过程中得到的解是在某个概率空间上的弱收敛结果。为了回到原始概率空间并证明概率意义下的强解,作者证明了路径唯一性结果,并应用Gyongy-Krylov方法恢复强收敛性。这一步对于建立真正的强路径解至关重要。

BD熵方法:这是证明全局适定性的核心技术。作者引入有效速度 $V = u + \mu(\rho)\partial_x\rho / \rho^2$,并考虑相应的BD熵泛函。通过仔细计算Itô公式并应用强 coercivity条件,推导出熵耗散不等式。该条件 $2\alpha-4 \leq \beta \leq 2\alpha-1$ 确保了熵耗散泛函的非负性,从而为控制真空状态和密度下界提供了关键估计。

新型变量与斜对称结构:为了克服Korteweg张量带来的导数损失问题,作者引入新变量 $A(\rho) = \partial_x(k(\rho)/\rho)$。这一变量变换揭示了系统的斜对称结构,使得高阶导数项之间产生本质抵消,从而获得更高阶的先验估计。

随机Gronwall引理与迭代估计:利用随机Gronwall引理,结合马尔可夫不等式和高阶Sobolev范数估计,作者建立了从局部解到全局解的延拓论证。通过迭代过程得到 $\rho \in H^{s+1}(\mathbb{T})$ 和 $u \in H^s(\mathbb{T})$($s > 7/2$)的范数控制。

4. 与之前工作的比较

本文的研究建立在可压缩流体力学和随机偏微分方程两个领域的丰富文献基础之上,同时在多个方向实现了实质性突破。

与经典可压缩Navier-Stokes方程的比较:经典的确定性和随机可压缩Navier-Stokes方程已有大量研究,Breit、Feireisl和Hofmanová等人的专著系统总结了相关理论。然而,当引入Korteweg张量后,系统的结构发生根本变化:动量方程中出现了密度的三阶导数项,而连续性方程关于速度出现导数损失。本文发展的方法无法简单套用经典理论,而需要借助新变量 $A(\rho)$ 建立的斜对称结构来处理这些技术困难。

与量子Navier-Stokes方程的比较:当 $\beta = -1$ 时,Navier-Stokes-Korteweg方程退化为量子流体动力学模型。此前的工作如[44]和[45]仅处理了这一特定情形。本文将结果推广到任意实数指数 $\beta$,覆盖了 $\beta = -1$(量子情形)、$\beta = 0$(经典Korteweg系统)以及更一般的情形,这是一个显著推广。

与确定性子流体力学文献的比较:在确定性设置下,Germain和LeFloch在[49]中引入了强 coercivity条件,为后续研究奠定了基础。近期Bresch等人的工作改进了参数范围。本文首次在随机框架下建立了相同的结果,并证明即使在无噪声情况下($F=0$),所得结论也是新的。

与BD关系的比较:许多已有工作假设粘性和毛细管系数通过特定的BD关系(如 $\beta = 2\alpha - 3$)耦合,从而简化分析。本文处理的是不满足BD关系的一般情形,技术难度更大但更具一般性。

随机紧性方法的创新:不同于此前随机流体力学工作主要处理常粘性系数情形,本文将多层逼近格式和随机紧性论证成功应用于带Korteweg张量的系统。Korteweg张量的非线性结构使得截断论证和紧性估计变得更加复杂,本文的方法为类似问题提供了可借鉴的范式。


2. 低韦伯数下厚气泡环的不存在性

Non-Existence of thick bubble rings at low Weber numbers

作者: Yuanjiang Han, Christian Seis

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24217v1

摘要翻译: 我们研究了自由边界毛细管欧拉方程框架下厚气泡环的存在性,重点关注低韦伯数区域。尽管已知椭球形气泡在此极限下会趋近于球形,但厚气泡环在低韦伯数下持续存在的可能性仍不确定。与允许厚涡环解的寻常欧拉方程相比,我们的分析表明,自由边界毛细管欧拉方程在低韦伯数下不支持厚气泡环的存在。这一区别凸显了表面张力对毛细管区域涡环行为的显著影响。

Comment: 无

链接: http://arxiv.org/abs/2603.24217v1

1. 研究对象和背景

本文研究了自由边界毛细管欧拉方程(free-boundary capillary Euler equations)框架下的厚气泡环(thick bubble rings)存在性问题,聚焦于低韦伯数(Weber numbers)这一物理 regime。在流体力学中,韦伯数是一个至关重要的无量纲参数,用于量化惯性力与表面张力之间的相对重要性。气泡环作为一种特殊的涡旋结构,其形成机制和稳定性在自然界和工程应用中都具有重要意义。典型的例子包括海洋哺乳动物在水下产生的气泡环,以及潜水员有意制造的气泡环现象。从数学建模的角度来看,研究者采用Young-Laplace定律来描述气泡环表面的压力分布,该定律建立了表面曲率与压力差之间的定量关系。

经典的涡旋环理论建立在普通欧拉方程的基础之上。1894年,Hill首次给出了完全显式的涡旋环解,尽管其形状呈完美球形,仅内部流面呈环状结构。1969年,Fraenkel成功构造了薄涡旋环(thin vortex rings),其核心半径远小于到旋转轴的主半径。随后,Norbury在稍晚些时候推导出了厚涡旋环(thick vortex rings),其主半径与核心半径具有可比性。这些经典结果表明,在普通欧拉方程框架下,厚涡旋环和薄涡旋环都是存在且稳定的。

然而,当引入表面张力效应后,情况发生了本质性的变化。本文作者指出,目前已知的存在于自由边界毛细管欧拉方程中的行波涡旋解仅有两类:Meyer和Seis构造的薄环形气泡环,以及Meyer、Niebel和Seis研究的椭球形气泡。特别值得注意的是,在低韦伯数条件下,椭球形气泡会趋近于球形,这与基本的物理直觉相一致。值得注意的是,相较于普通欧拉方程仅允许Hill球形涡旋这一种单连通稳态涡旋构型,自由边界毛细管欧拉方程在椭球形解方面展现出更大的灵活性。

本文的核心问题是:与普通欧拉方程中厚涡旋环的存在性形成鲜明对比的是,自由边界毛细管欧拉方程在低韦伯数条件下是否允许厚气泡环的存在?这一问题的答案涉及表面张力对涡旋环行为的深刻影响,体现了自由边界毛细管欧拉方程研究中灵活性与刚性之间的微妙平衡。

2. 主要定理或主要结果

本文的核心贡献是建立了厚气泡环的非存在性定理,该定理揭示了表面张力对涡旋环稳定性的关键约束作用。

定理1:存在正常数 $C>0$,使得对任意满足曲率条件、总平均曲率非正 $(10)$ 以及最大原理 $(9)$ 的方程组 $(1)$、$(2)$、$(3)$、$(4)$、$(5)$ 的解 $(E,\psi,W,\gamma,\lambda)$,都有如下韦伯数下界估计

$$ \mathrm{We} \geq C\left(\frac{1}{\mu+\mu^{3}}+\frac{\delta}{\mu^{2}}\right) $$

其中 $\mu = R/|E|^{1/2}$,而 $\delta$ 是刻画环几何位置与对称轴接近程度的厚度度量,定义为

$$ \delta := \int_{E} \frac{1}{r^{2}} d(r,z) - 2\pi $$

该定理的推论表明,当气泡环的横截面满足 $2\pi R^{2} \leq |E|$ 这一几何条件时,厚气泡环的韦伯数必须满足类似的下界估计 $\mathrm{We} \geq C(1+\delta)$。特别地,对于与Norbury涡旋环形状相似的任何厚气泡环,韦伯数下界可进一步估计为

$$ \mathrm{We} \geq \frac{CR}{\mathrm{dist}(E,\partial R_{+}^{2})} $$

这一结果表明,Norbury的扰动构造方法无法在固定韦伯数下推广到气泡环的情形。

从物理意义上看,该定理意味着:当韦伯数足够低(表面张力效应占主导)时,厚气泡环解在数学上是不存在的。这与普通欧拉方程中的情况形成鲜明对比——在后者框架下,Norbury的厚涡旋环解是已知存在的。这一差异深刻揭示了表面张力在毛细管 regime 中对涡旋环行为的刚性约束效应。

3. 研究方法、关键技术和核心工具

本文的证明策略建立在精细的偏微分方程估计技术与几何分析的深度融合之上。

数学模型与无量纲化:研究者从描述气泡环的过定边界问题出发,该问题包含椭圆方程 $(1)$(描述环外无旋流动)、Dirichlet型边界条件 $(2)$(流函数约束)和Neumann型边界条件Young-Laplace方程 $(3)$(表面张力与曲率的关系)。通过引入无量纲变量 $(r,z) = (a\hat{r},a\hat{z})$ 和 $\psi = a\beta\hat{\psi}$,问题被归一化为 $\beta=1$、$|E|=2\pi$ 的标准形式,从而使得韦伯数成为控制参数。归一化后的Young-Laplace跳跃条件 $(15)$ 建立了曲率、伯努利常数与速度场之间的代数关系。

关键几何引理:引理1揭示了总平均曲率非正条件 $(10)$ 与厚度度量 $\delta \geq 0$ 之间的等价性,证明了

$$ \int_{\partial E} H ds + \delta = 0 $$

这一恒等式通过将平均曲率分解为子午曲率和方位曲率,并应用Gauss-Bonnet定理和散度定理而得。引理2建立了横截面积下界 $2\pi R^{2} \leq |E|$ 与厚度条件的蕴含关系,其证明运用了Cauchy-Schwarz不等式的两次迭代。

伯努利常数非负性引理:引理3是连接几何条件与韦伯数下界的关键桥梁。通过对归一化跳跃条件 $(15)$ 在边界 $\partial E$ 上积分,并利用曲率条件 $(10)$ 和引理1的恒等式,可得

$$ \lambda|\partial E| = \int_{\partial E} \left(\mathrm{We} \frac{\partial \psi}{\partial n} - Wn\cdot e_{r}\right)^{2} ds + \delta \geq \delta \geq 0 $$

这一估计表明,在厚环假设下伯努利常数必须非负。

几何凸性引理:引理4给出了气泡环横截面 $E$ 的几何约束:若 $R_{\max} = \max\{r>0:(r,z)\in E\}$,则 $R_{\max} \leq 3R$,其中 $R$ 是由面积定义的主半径。该引理的证明涉及构造包含于 $E$ 的三角形和包含 $E$ 的梯形,通过体积比较和显式积分计算,最终导出 $(k-1)^{3} \leq 3k-1$ 这一代数不等式,并解得 $k \leq 3$。该引理表明常数3是最优的,因为等号可由关于z轴对称的三角形实现。

韦伯数下界命题:命题1在伯努利常数非负的假设下,建立了韦伯数的下界估计。该命题的证明利用了横截面的水平宽度函数 $w(z)$ 的精细分析,通过对流函数和几何量的综合估计而完成。定理1的完整证明由引理3、命题1和定义 $(14)$ 直接推得。

4. 与之前工作的比较

本文的研究定位于自由边界毛细管欧拉方程领域的核心问题,并与该领域的已有工作形成鲜明的对比与补充关系。

与普通欧拉方程的比较:在普通欧拉方程的框架下,厚涡旋环的存在性已由Norbury在1970年代建立。Norbury的解具有与Hill球形涡旋相同的拓扑结构,其环面流面最接近对称轴,厚度度量 $\delta \sim R/\mathrm{dist}(E,\partial R_{+}^{2}) \gg 1$ 表明其显著偏离对称轴。然而,本文证明了一个深刻的刚性现象:在引入表面张力效应后,这种厚环结构在低韦伯数条件下无法保持稳定。具体而言,本文给出的韦伯数下界 $\mathrm{We} \geq CR/\mathrm{dist}(E,\partial R_{+}^{2})$ 意味着,当环足够厚(接近对称轴)时,韦伯数必须足够大,这与低韦伯数 regime 不相容。这一发现揭示了表面张力对涡旋环行为的本质性约束。

与薄气泡环构造的比较:Meyer和Seis在先前的工作中成功构造了薄环形气泡环($a \ll R$),其理论适用于任意韦伯数范围。与之相对,本文结果表明厚环($a \sim R$)的存在性存在韦伯数下界,这一差异源于厚环与薄环在几何和流体动力学上的本质区别:薄环可通过渐近分析处理,而厚环需要整体性估计。

与椭球形气泡研究的比较:Meyer、Niebel和Seis的椭球形气泡研究表明,在低韦伯数条件下,椭球形气泡趋近于球形,这与本文关于厚环非存在性的结论形成有趣的对照。研究者特别指出,自由边界毛细管欧拉方程在椭球形解方面比普通欧拉方程更具灵活性(允许更多稳态构型),但在环状解方面却呈现出更强的刚性(厚环不存在)。这种灵活性与刚性的交织根源于涡旋构型的拓扑性质。

与平面情况的联系:Niebel在平面毛细管自由边界欧拉方程中建立了相关刚性结果:低韦伯数条件下,除球形外的其他稳态气泡构型均不存在。本文将这一刚性现象从平面推广到轴对称情形,证明其具有更广泛的适用性。

遗留的开问题:本文明确指出,厚气泡环在高韦伯数条件下是否存在仍是未解决的公开问题,这为后续研究指明了方向。从物理直觉上看,当韦伯数足够大(惯性占主导)时,表面张力效应减弱,厚气泡环有可能类似于Norbury的涡旋环而存在,但这一猜想尚待严格的数学证明。


3. 具有接触间断的二维正压可压缩欧拉系统的容许弱解的非唯一性

Non-uniqueness of admissible weak solutions to the two-dimensional barotropic compressible Euler system with contact discontinuities

作者: Kotaro Horimoto

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.23921v1

摘要翻译: 本文研究了具有一般严格递增压力定律的二维正压可压缩欧拉系统的黎曼问题。通过凸积分方法,对于特定的黎曼初值数据,建立了无限多个容许弱解的存在性。这些初值数据对应的一维自相似解仅由接触间断构成。

Comment: 无

链接: http://arxiv.org/abs/2603.23921v1

1. 研究对象和背景

本文研究二维全空间中的二维等熵可压缩欧拉系统的初值问题(黎曼问题)。该系统的未知量是密度 $\rho = \rho(t,x) > 0$ 和动量 $m = m(t,x) \in \mathbb{R}^2$,由以下质量守恒和动量守恒方程描述:

$$ \partial_t \rho + \text{div}\, m = 0 \quad \text{in} \quad (0,\infty) \times \mathbb{R}^2, $$
$$ \partial_t m + \text{div}\left(\frac{m \otimes m}{\rho}\right) + \nabla p(\rho) = 0 \quad \text{in} \quad (0,\infty) \times \mathbb{R}^2. $$

压力函数 $p$ 满足 $p \in C^1(\mathbb{R}^+; \mathbb{R}^+)$ 且 $p'(\rho) > 0$(严格递增),这涵盖了多项式压力 $p(\rho) = \rho^\gamma$($\gamma \geq 1$)等常用模型。研究的核心问题是该双曲守恒律系统的解的存在性和唯一性。

在一维空间中,容许性条件(熵条件)确保了 Glimm 构造的容许弱解在 BV 函数类中的唯一性。然而在高维空间中,唯一性通常不成立。De Lellis 和 Székelyhidi 在不可压缩欧拉系统开创性地发展了凸积分框架,证明了非唯一性现象。Chiodaroli-De Lellis-Kreml 等后续工作表明,当一维自相似解包含激波时会出现非唯一性,而仅由稀疏波组成的自相似解则保持唯一性。

本文关注的是此前研究较少的接触间断情形。当一维自相似解仅由单个接触间断组成时,容许弱解的唯一性问题在很大程度上是开放的。本文针对满足特定对称性条件的接触间断黎曼数据,证明存在无限多个容许弱解。

2. 主要定理或主要结果

本文的主要结果是以下非唯一性定理:

定理 1.3:假设压力函数 $p$ 满足严格递增条件 (1.5)。任意给定 $\rho_0 > 0$ 和 $u_0 \neq 0$。设 $\rho_+ = \rho_- = \rho_0$,$m_+ = (\rho_0 u_0, 0)$,$m_- = (-\rho_0 u_0, 0)$。则存在无限多个容许弱解满足黎曼初值条件。

该定理的重要意义体现在以下方面:

第一,这是首次证明对于任意严格递增的 $C^1$ 压力定律都存在非唯一性,突破了此前 Krupa-Székelyhidi 的结果仅适用于精心构造的压力函数。论文明确指出,非唯一性现象并不依赖于激波的存在——即使自相似解仅由接触间断组成,同样会出现无限多个容许弱解。

第二,构造的容许弱解是"真正二维的",即它们同时依赖于两个空间变量 $x$ 和 $y$。根据文献 [18] 中的 Theorem 1.2,在接触间断黎曼数据的 L^\infty 函数类中,一维容许弱解是唯一的。因此,本文获得的无限多个容许弱解必然表现出真正的二维振荡特征。

第三,该结果建立了可压缩欧拉系统与不可压缩欧拉系统之间的深刻联系:接触间断在可压缩情形下类似于不可压缩情形中的涡面(vortex sheet),而本文证明的非唯一性现象与 Székelyhidi 对不可压缩欧拉系统的开创性结果遥相呼应。

3. 研究方法、关键技术和核心工具

本文采用的核心工具是 Markfelder 在文献 [20] 中发展的精化凸集成方法。该方法相较于早期框架(如 De Lellis-Székelyhidi 及其在可压缩情形的推广)具有显著优势:将熵不等式直接整合到凸积分框架中,而非单独验证。

具体而言,研究方法包含以下关键技术要素:

五区域扇形划分:传统凸积分方法通常将时空区域分解为三个区域 Γ⁻、Γ₁ 和 Γ⁺,在单一的中间区域 Γ₁ 应用凸积分生成无限多解。然而,对于本文考虑的接触间断黎曼数据,三区域或四区域划分不足以构造满足所有约束条件的容许扇形子解。因此,论文引入更精细的五区域划分:Γ⁻、Γ₁、Γ₂、Γ₃、Γ⁺,每个区域由线性界面 $y = \mu_i t$($i=0,1,2,3$)分隔,速度满足 $\mu_0 < \mu_1 < \mu_2 < \mu_3$。

容许扇形子解的定义:该框架下的容许扇形子解是一个分片常数函数元组 $(\rho,m,U,q,F)$,其中 $PH = \mathbb{R}^2 \times \text{Sym}_0(2,\mathbb{R}) \times \mathbb{R} \times \mathbb{R}^2$。各区域的状态通过代数方程和不等式约束,包括 Rankine-Hugoniot 条件、熵不等式和子解条件。特别值得注意的是,早期框架将能量通量 $F$ 固定为 $F = m \frac{q + P(\rho)}{\rho}$,而 Markfelder 的方法将 $F$ 视为额外未知量,提供了处理熵不等式的灵活性。

对称性假设:基于初值数据的对称性 $(\rho_+, m_+) = (\rho_-, -m_-)$,构造过程采用以下对称性假设:

$$ (\rho_1, m_1, U_1, q_1, F_1) = (\rho_3, -m_3, U_3, q_3, -F_3), $$
$$ (\mu_0, \mu_1, \mu_2, \mu_3) = (-b, -a, a, b), \quad 0 < a < b. $$

这一假设大大简化了代数系统的复杂度,使得复杂的 Rankine-Hugoniot 条件简化为显式代数关系(如 Lemma 3.1 所示)。

代数系统的求解:根据 Proposition 2.7,构造容许扇形子解的任务转化为寻找满足代数方程组 (2.4)-(2.10) 的常数。论文通过引理 3.1-3.3 系统地化简和验证这些条件:Lemma 3.1 将 Rankine-Hugoniot 条件约化为 $\rho_1, \rho_2$ 和 $m_1$ 的显式表达式;Lemma 3.3 证明在特定能量通量选择下,熵不等式可归结为单一代数不等式 (3.10)。

4. 与之前工作的比较

本文的研究建立在前人工作的基础之上,同时在多个关键方面实现了突破:

与 De Lellis-Székelyhidi 工作的比较:文献 [11, 12] 为不可压缩 Euler 系统开发了凸积分框架,证明了非唯一性。本文将类似思想推广到可压缩情形,但面临额外的技术挑战——可压缩系统具有密度变量且熵条件更为复杂。Markfelder 的精化框架正是为克服这些挑战而发展的。

与 Chiodaroli-De Lellis-Kreml 工作的比较:文献 [6] 针对多项式压力 $p(\rho) = \rho^2$ 的情形,证明含激波的黎曼数据存在非唯一性。本文关注的是不同的间断类型——接触间断,并证明非唯一性同样适用于任意严格递增压力定律(不仅限于 $\gamma = 2$ 的特例)。

与 Feireisl-Kreml 工作的比较:文献 [14] 证明了仅由稀疏波组成的一维自相似解在容许弱解类中是唯一的。本文结果与此一致——当解退化为严格一维函数时唯一性成立,但允许真正的二维振荡时则出现非唯一性。

与 Krupa-Székelyhidi 工作的比较:文献 [18] 在对称性条件 (1.9) 下,针对特定构造的压力函数证明了接触间断数据的非唯一性。本文推广了该结果:证明对任意严格递增的 $C^1$ 压力定律都存在非唯一性,从而回答了文献 [18] 中悬而未决的问题——非唯一性现象并非压力函数设计的人工产物,而是可压缩 Euler 系统的本质特征。

理论意义:本文最重要的理论贡献在于证伪了"激波是非唯一性必要条件"这一此前可能的推测。研究表明,接触间断同样可以导致非唯一性,这对可压缩流体动力学中弱解的理论理解具有深远影响。


4. 稳态纳维-斯托克斯方程的精化李型定理

Refined Liouville-Type Theorems for the Stationary Navier–Stokes Equations

作者: Youseung Cho, Minsuk Yang

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.23833v1

摘要翻译: 我们研究三维稳态纳维-斯托克斯方程的光滑解,并在精化的衰减假设下建立新的李型定理。基于Cho等人[Cho et al.]的工作,我们对已知的可积性准则进行了精化,并分析了相关的平均量。我们的主要结果表明,如果某个解的$L^p$增长速率在$3/2 < p < 3$范围内保持有界,则该解必为平凡解。证明过程综合运用了平均衰减估计、能量不等式以及迭代格式。

Comment: 无

链接: http://arxiv.org/abs/2603.23833v1

1. 研究对象和背景

本文研究三维静止Navier-Stokes方程的光滑解及其性质。静止Navier-Stokes方程描述了不可压缩流体在稳态流动时的速度场$u$和压力场$\pi$的数学关系,其控制方程为

$$ -\Delta u + (u \cdot \nabla)u + \nabla \pi = 0, \quad \nabla \cdot u = 0. $$

Liouville型定理是偏微分方程理论中的重要结果,它揭示了在特定条件下,唯一满足方程的解只能是平凡解(即恒为零或为常数)。在流体动力学背景下,这意味着在某些衰减或可积性假设下,稳态流动只能处于完全静止的状态。经典的Liouville型定理要求解具有某种整体可积性,如Galdi证明的$u \in L^{9/2}(\mathbb{R}^3)$可推出解的平凡性。近年来,Seregin、Wang、Tsai以及Cho等人的工作进一步发展了不同框架下的Liouville型定理,包括Lorentz空间中的结果和带有增长条件的推广形式。本文在此基础上,通过引入额外的增长函数$g(\rho)$来精细化已有的可允许增长速率条件,从而建立更一般化的Liouville型判据。

2. 主要定理或主要结果

本文建立了两个主要的Liouville型定理,它们构成了论文的核心贡献。

定理1(Theorem 1)设$g$满足假设条件1。假设$u$是方程的光滑解且满足两个条件:其一,$\nabla u \in L^2(\mathbb{R}^3)$;其二,存在$0 < \theta < 1$和$1 \leq p < 3$使得

$$ \limsup_{\rho \to \infty} \frac{\|u\|_{L^p(A(\theta\rho,\theta^{-1}\rho))}}{\rho^{\frac{2p-1}{3}}g(\rho)^{\frac{3}{p}-1}} < \infty. $$

则$u \equiv 0$。

定理2(Theorem 2)设$g$满足假设条件1。假设$u$是方程的光滑解且存在$0 < \theta < 1$和$3/2 < p < 3$满足上述增长条件(6),则$u \equiv 0$。该定理的重要突破在于不需要假设$\nabla u \in L^2(\mathbb{R}^3)$,尽管证明这一结论并非易事。

本文的核心创新在于引入了假设条件1中定义的精细化增长函数$g(\rho)$,它需要满足三个性质:非负性、$\lim_{\rho \to \infty} \rho^{-1/3}g(\rho) = 0$以及特定的积分发散条件

$$ \int_1^\infty \frac{d\rho}{g(\rho)\rho} = \infty. $$

这些条件确保了增长函数足够缓慢地发散,从而能够推导出解的平凡性。论文中给出的典型例子包括迭代对数函数如$\log(e+\rho)$、$\log(e+\log(e+\rho))$等,它们都满足假设条件。

3. 研究方法、关键技术和核心工具

本论文采用能量方法作为主要研究框架,结合平均衰减估计和迭代技巧来建立Liouville型判据。

能量函数$E_\theta(\rho)$的构造与微分性质是证明的核心工具之一。论文定义了

$$ E_\theta(\rho) = \int_{\mathbb{R}^3} |\nabla u(x)|^2 \eta_\theta\left(\frac{|x|}{\rho}\right) dx, $$

其中$\eta_\theta$是一个截断函数,在$[0,\theta]$上取值为1,在$[1,\infty)$上取值为0,中间线性过渡。引理1证明了$E_\theta(\rho) \in C^1((0,\infty))$并给出了其导数的精确表达式

$$ E_\theta'(\rho) = \frac{1}{\rho^2(1-\theta)} \int_{A(\theta\rho,\rho)} |\nabla u(x)|^2 |x| dx. $$

这个公式建立了能量函数与解在环形区域上梯度的$L^2$范数之间的微分关系。

局部能量估计是建立全局性质的关键技术。引理3、引理4和引理5通过选取适当的测试函数并利用散度为零的性质,导出了一系列关于$u$和$\nabla u$在球体和环形区域上范数的不等式。引理3特别证明了如果$\liminf_{\rho \to \infty} K_\theta(\rho) = 0$,其中$K_\theta(\rho) = \rho^{-1}\|u\|_{L^3(A(\theta\rho,\theta^{-1}\rho))}$,则解必须是平凡的;如果$\liminf K_\theta(\rho) < \infty$,则$\nabla u \in L^2(\mathbb{R}^3)$且$u \in L^6(\mathbb{R}^3)$。

**引理2中的线性算子$T$**在处理压力项时发挥了关键作用。该引理(源于Tsai的工作)表明存在一个从$L^q(A(\theta R,R))$到$W_0^{1,q}(A(\theta R,R))$的线性映射$T$,使得$\nabla \cdot (Tf) = f$且具有范数估计

$$ \|\nabla Tf\|_{L^q(A(\theta R,R))} \leq C_{\theta,q}\|f\|_{L^q(A(\theta R,R))}. $$

利用这个算子可以消除能量估计中的压力项,这是处理Navier-Stokes方程的标准技巧。

迭代论证(引理8的推广形式)用于从局部能量估计推导出全局衰减性质。通过对$r$和$R$进行精细的分步迭代,可以将局部信息传播到更大的区域,最终得到关于解在无穷远处行为的全局结论。这种技术在引理4和引理6的证明中得到了充分应用。

矛盾假设与积分发散条件的结合是定理1证明中最巧妙的部分。假设存在$C > 0$使得对所有足够大的$\rho$有

$$ \|\nabla u\|_{L^2(A(\theta\rho,\theta^{-1}\rho))} > \frac{C}{\sqrt{g(\rho)}}. $$

通过对$g$的非递减性和假设条件5中给出的积分发散性质进行级数估计,可以推导出

$$ \sum_{n=N}^\infty \frac{1}{g(\theta^{-2n})\theta^{-2n}} \leq -\frac{1}{2\log\theta} \sum_{n=N}^\infty \frac{1}{g(\theta^{-2n})} < \infty, $$

这与积分发散条件矛盾,最终证明解的梯度必须以足够快的速率衰减至零。

4. 与之前工作的比较

本文的研究建立在Cho等人先前工作的基础上,对已有的Liouville型定理进行了实质性的推广和精细化。

与Galdi结果的比较:Galdi在早期工作中证明了如果$u \in L^{9/2}(\mathbb{R}^3)$,则解是平凡的。该结果的衰减条件可表述为

$$ \lim_{\rho \to \infty} \frac{1}{\rho} \int_{A(\rho,2\rho)} |u|^3 dx = 0, $$

这可以由Hölder不等式在$L^{9/2}$可积性下推出。本文的结果不再要求解属于某个固定的$L^p$空间,而是允许解具有更一般的增长行为,通过引入增长函数$g(\rho)$来刻画这种增长。

与Seregin-Wang结果的比较:Seregin和Wang建立了针对$p > 3$、$3 \leq l \leq \infty$(或$p = l = 3$)的不等式

$$ \|\nabla u\|_{L^2(\mathbb{R}^3)} \leq C \liminf_{\rho \to \infty} \frac{\|u\|_{L^{p,l}(A(\rho,2\rho))}}{\rho^{\frac{9}{p}-2}}. $$

他们还在Lorentz空间中导出了衰减判据

$$ \liminf_{\rho \to \infty} \frac{\|u\|_{L^{p}(A(\rho,2\rho))}}{\rho^\gamma} < \infty $$

对某些$1/2 < p < 3$和$\gamma < 2 - \frac{1}{p \cdot \frac{5}{3}}$成立。本文的结果通过增长函数$g$将这些不同形式的条件统一到一个框架下,并覆盖了更广泛的参数范围。

与Tsai结果的比较:Tsai证明了如果存在$1/2 \leq p \leq 3$使得

$$ \liminf_{\rho \to \infty} \frac{\|u\|_{L^{p}(A(\rho,2\rho))}}{\rho^{2-\frac{1}{p \cdot \frac{5}{3}}}} = 0, $$

则解是平凡的。本文的结果虽然要求更强的有界性而非收敛到零,但允许更一般的增长函数形式,并且将参数范围精确到$1 \leq p < 3$。

与Cho等人近期工作的比较:Cho等人在最近的研究中证明了如果存在$3/2 < p < 3$使得

$$ \liminf_{\rho \to \infty} \frac{\|u\|_{L^{p}(A(\rho,2\rho))}}{\rho^{2-\frac{1}{p \cdot \frac{5}{3}}}} < \infty, $$

则解是平凡的。本文在此基础上引入了额外的增长函数$g(\rho)$,将"$\rho^{2-\frac{1}{p \cdot \frac{5}{3}}}$“这一已知的尖锐增长率推广到”$\rho^{\frac{2p-1}{3}} g(\rho)^{\frac{3}{p}-1}$“的更一般形式。这种推广的优势在于:当$g(\rho)$恒为常数时,本文结果退化为Cho等人的结果;而当$g(\rho)$缓慢增长时(如对数函数),本文的判据能够涵盖更广泛的解类,这是一个实质性的推广。

与势函数框架下结果的比较:另一类相关研究假设$u = \nabla \cdot V$并对势函数$V$施加条件。Seregin处理了$V \in \text{BMO}(\mathbb{R}^3)$的 skew-symmetric情形,Chae、Wolf、Cho等人以及Bang、Yang将这一框架推广到在_large balls_上的增长条件。本文的结果采用了不同的方法,直接在速度场上施加增长条件,避免了引入额外势函数的复杂性,同时在技术上也更加简洁。

综合来看,本文的主要贡献在于提出了一个统一且精细化的Liouville型判据框架,通过增长函数$g(\rho)$的灵活性,既包含了已有的经典结果,又允许更一般的解的存在性条件,从而推进了该领域的理论发展。


了解领域论文(摘要翻译)

1. 正则化Prabhakar分数阶导数边值问题的格林函数框架

Green’s Function Framework for Boundary Value Problems with the Regularized Prabhakar Fractional Derivative

作者: Erkinjon Karimov, Doniyor Usmonov, Maftuna Mirzaeva

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24252v1

链接: http://arxiv.org/abs/2603.24252v1

摘要翻译

中文标题: 正则化Prabhakar分数阶导数边值问题的格林函数框架

摘要翻译: 本文研究了涉及正则化Prabhakar分数阶导数的次扩散方程的第一初边值问题。通过叠加法,将该问题转化为两个初边值问题进行求解,获得了问题的显式解及相应的格林函数。格林函数的显式形式由二元Mittag-Leffler型函数表示。随后,证明了所获得的解确实构成所考察问题的真实解。


2. Rayleigh-Stokes型分数阶方程的非局部时间问题

Non-local time problem for the Rayleigh–Stokes type fractional equations

作者: Ravshan Ashurov, Yusuf Fayziyev, Nuriddin Khushvaktov

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24085v1

链接: http://arxiv.org/abs/2603.24085v1

摘要翻译

中文标题: Rayleigh-Stokes型分数阶方程的非局部时间问题

摘要翻译: 尽管人们对经典流体动力学方程的分数阶推广日益关注,但分数阶Rayleigh-Stokes问题此前几乎仅使用Riemann-Liouville分数阶导数进行研究。据作者所知,Caputo导数情形的解的显式解析形式在文献中尚未建立,且在本文工作之前,对该表述形式的适定性、唯一性或正则性性质尚未进行系统性研究。

本文通过研究具有阶数$\rho\in(0, \, 1)$的Caputo分数阶时间导数的Rayleigh-Stokes方程来填补这一空白。利用拉普拉斯变换和傅里叶方法,以及特殊函数,我们对该相应的初始边值问题、非局部问题和倒向问题进行了严格的适定性分析。


3. 符号化KAN:具有离散符号结构的科尔莫戈罗夫-阿诺德网络用于可解释学习

Symbolic–KAN: Kolmogorov-Arnold Networks with Discrete Symbolic Structure for Interpretable Learning

作者: Salah A Faroughi, Farinaz Mostajeran, Amirhossein Arzani, Shirko Faroughi

类别: cs.LG, cs.CE, math.AP, math.DS

发布日期: 2026-03-25

arXiv ID: 2603.23854v1

链接: http://arxiv.org/abs/2603.23854v1

摘要翻译

中文标题: 符号化KAN:具有离散符号结构的科尔莫戈罗夫-阿诺德网络用于可解释学习

摘要翻译:

控制方程的符号发现是科学机器学习领域长期以来的重要目标,然而在可解释性与可扩展学习之间始终存在根本性的权衡。传统的符号回归方法能够产生明确的解析表达式,但依赖于组合搜索;而神经网络能够随着数据和维度增加而高效扩展,但产生的表示却不透明。在本工作中,我们提出了符号科尔莫戈罗夫-阿诺德网络(Symbolic-KANs),这是一种通过在可训练的深度网络中直接嵌入离散符号结构来弥合上述差距的神经网络架构。符号化KAN将多元函数表示为由学习到的一元基元对学习到的标量投影进行组合的结果,该过程由解析基元库、层级门控机制以及符号正则化引导,符号正则化逐渐将连续混合尖锐化为独热选择。经过门控训练和离散化后,每个激活单元选择单一的基元和投影方向,从而产生紧凑的闭式表达式,无需进行后验符号拟合。符号化KAN还可作为可扩展的基元发现机制,识别最相关的解析分量,这些分量随后可用于为稀疏方程学习方法提供候选库。我们证明,符号化KAN能够在数据驱动回归和逆动力系统中可靠地恢复正确的基元项和控制结构。此外,该框架还可扩展到偏微分方程的前向和逆物理信息学习,能够直接从控制约束中产生精确解,同时构建紧凑的符号表示,其所选基元反映了底层方程的真实解析结构。这些结果表明,符号化KAN是实现可扩展、可解释且基于机理的控制定律学习的重要一步。


不相关论文(基本信息)

1. 粘声波方程的奇点传播与反问题

Propagation of singularities and inverse problems for the viscoacoustic wave equation

作者: Giovanni Covi, Maarten de Hoop, Mikko Salo

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24497v1

链接: http://arxiv.org/abs/2603.24497v1

摘要: We study an inverse problem for the viscoacoustic wave equation, an integro-differential model describing wave propagation in viscoacoustic media with memory in the leading order term. The medium is characterized by a spatially varying sound speed and a space-time dependent memory kernel. Assuming that waves are generated by sources supported outside the region of interest, we consider exterior measurements encoded by the source-to-solution map. To study this inverse problem, we construct solutions concentrating near fixed geodesics and establish a corresponding propagation of singularities result for the semiclassical wave front set. These results are valid without any restriction on the underlying sound speed. Then, under certain geometric conditions, we prove that the exterior data uniquely determine not just the sound speed inside the domain but also all time derivatives at zero of the memory kernel. This involves a reduction to the lens rigidity and geodesic ray transform inverse problems. As an application, we establish uniqueness for the recovery of variable parameters in the extended Maxwell model.


2. 带电毛细液滴的非局域等周模型杨氏定律

Young’s law for a nonlocal isoperimetric model of charged capillarity droplets

作者: Michael Goldman, Matteo Novaga, Adriano Prade

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24483v1

链接: http://arxiv.org/abs/2603.24483v1

摘要: We study a variational problem modeling equilibrium configurations of charged liquid droplets resting on a surface under a convexity constraint. In the two-dimensional case with Coulomb interactions, we establish the validity of Young’s law for the contact angle for small enough charges.


3. 刘维尔定理与周期数据下抛物型Monge-Ampère方程的精确可解性

Liouville theorem and sharp solvability for solutions of the parabolic Monge-Ampère equation with periodic data

作者: Kui Yan, Jiguang Bao

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24479v1

链接: http://arxiv.org/abs/2603.24479v1

摘要: We prove a Liouville Theorem for ancient solutions of the parabolic Monge-Ampère equation with smooth periodic data, generalizing Caffarelli-Li’s result \cite{cl04} in 2004 to the parabolic background. To achieve this, we obtain a necessary and sufficient condition for the existence of the smooth periodic solution of the equation $\left(1-u_t\right)\det \left(D_x^2u+I\right)=f$ in $\mathbb{R}^{n+1}$, where $f$ is smooth and periodic in both spatial and temporal variables. This parabolic existence theorem parallels the elliptic counterpart established by Li \cite{l90} in 1990.


4. 不育昆虫技术控制埃及伊蚊的时空Ricker型模型分析与数值模拟

Analysis and numerical simulation of a spatio-temporal Ricker-type model for the control of Aedes aegypti mosquitoes with Sterile Insect Techniques

作者: Oscar Eduardo Escobar-Lasso, Stefan Frei, Reinhard Racke, Olga Vasilieva

类别: math.NA, math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24460v1

链接: http://arxiv.org/abs/2603.24460v1

摘要: Sterile Insect Technique (SIT) is widely regarded as a promising, environmentally friendly and chemical-free strategy for the prevention and control of dengue and other vector-borne diseases. In this paper, we develop and analyze a spatio-temporal reaction-diffusion model describing the dynamics of three mosquito subpopulations involved in SIT-based biological control of Aedes aegypti mosquitoes. Our sex-structured model explicitly incorporates fertile females together with fertile and sterile males that compete for mating. Its key features include spatial mosquito dispersal and the incorporation of spatially heterogeneous external releases of sterile individuals. We establish the existence and uniqueness of global, non negative, and bounded solutions, guaranteeing the mathematical well-posedness and biological consistency of the system. A fully discrete numerical scheme based on the finite element method and an implicit-explicit time-stepping scheme is proposed and analyzed. Numerical simulations confirm the presence of a critical release-size threshold governing eradication versus persistence at a stable equilibrium with reduced total population size, in agreement with the underlying ODE dynamics. Moreover, the spatial structure of the model allows us to analyze the impact of spatial distributions, heterogeneous releases, and periodic impulsive control strategies, providing insight into the optimal spatial and temporal deployment of SIT-based interventions.


5. 带慢扰动项的抛物型Monge-Ampère方程古代解在无穷远处的最优渐进行为

Optimal Asymptotic Behavior at Infinity of Ancient Solution to the Parabolic Monge-Ampère Equation with Slow Perturbation Term

作者: Kui Yan, Jiguang Bao

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24457v1

链接: http://arxiv.org/abs/2603.24457v1

摘要: In this paper, we obtain optimal asymptotic behavior of parabolically convex $C^{2,1}$ solution to the parabolic Monge-Ampère equation $-u_t\det D_x^2u=f$, where $f$ converges to $1$ at infinity with a slow rate. This result extends the elliptic estimate in \cite{lb5} to the parabolic setting.


6. 带有周期数据的抛物型Monge-Ampère方程古老解的刘维尔定理

A Liouville theorem for ancient solutions of the parabolic Monge-Ampère equation with periodic data

作者: Kui Yan, Bao jiguang

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24452v1

链接: http://arxiv.org/abs/2603.24452v1

摘要: This article is concerned with the parabolic Monge-Ampère equation $-u_t\det D_x^2u=f$, where $f=f_1(x)f_2(t)$ and $f_1,f_2$ are positive periodic functions. We prove that any classical parabolically convex ancient solution $u$ must be of the form $-τt+p(x)+v(x,t)$, where $τ$ is a positive constant, $p(x)$ is a convex quadratic polynomial, and $v$ inherits both the spatial and temporal periodicity from $f$. This work extends previous contributions by Caffarelli-Li \cite{cl04} on periodic frameworks for the elliptic Monge-Ampère equations, and generalizes Zhang-Bao \cite{zb18}’s Liouville theorem for $f_2\equiv1$ in parabolic case.


7. 具有双幂非线性的伪相对论薛定谔方程的增强基态

Boosted Ground States for a Pseudo-Relativistic Schrödinger Equation with a double power nonlinearity

作者: Pietro d’Avenia, Alessio Pomponio, Gaetano Siciliano, Lianfeng Yang

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24449v1

链接: http://arxiv.org/abs/2603.24449v1

摘要: In this paper, we investigate the existence and limit behaviours of travelling solitary waves of the form $ψ(t,x)=e^{iλt}\varphi\left(x-vt\right)$ to the nonlinear pseudo-relativistic Schrödinger equation

$$ i\partial_t ψ=(\sqrt{-Δ+m^2})ψ- |ψ|^{\frac{2}{N}}ψ-μ|ψ|^{q}ψ~~\text{ on }\mathbb{R}^N, $$

for $m\ge 0$ and $|v|<1$. To this end, we introduce and analyse an associated constrained variational problem, whose minimizers are termed boosted ground states and the parameter $λ$ is obtained as a Lagrangian multiplier. We first provide a complete classification for the existence and nonexistence of such boosted ground states. Based on this classification, we then study several limiting profiles, for which the exact blow-up rate is also established.


8. 球面上拉普拉斯-贝尔特拉梅方程的平面波表示——在格林函数中的应用

Plane-wave representation for the Laplace–Beltrami equation on a sphere. Application to the Green’s function

作者: Andrey V. Shanin, Valentin D. Kunz, Raphael C. Assier

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24417v1

链接: http://arxiv.org/abs/2603.24417v1

摘要: We propose an extension of the plane-wave representation for wave fields defined on the real sphere $§^2$. This representation is well-known in the planar setting but has never been developed for curved surfaces. To achieve this, we need to carefully study the geometry of the complexification of $§^2$ and the properties of the Laplace–Beltrami operator, while using concepts of multidimensional complex analysis. We extend the region of validity of such plane-wave representation by developing a sliding-contours method. Our methodology is illustrated through the study of the Green’s function on the real sphere.


9. 沿永生Kähler-Ricci流的高阶Ricci估计

Higher-order Ricci estimates along immortal Kähler-Ricci flows

作者: Wenrui Kong

类别: math.DG, math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24380v1

链接: http://arxiv.org/abs/2603.24380v1

摘要: We study higher-order curvature estimates along Kähler-Ricci flows on compact Kähler manifolds of intermediate Kodaira dimension. We prove that away from singular fibers, the Ricci curvature is uniformly bounded in $C^1$, the Laplacian of the Ricci curvature in $C^0$, and the scalar curvature in $C^2$. We identify a geometric obstruction to higher-order curvature bounds, whose non-vanishing causes a specific third-order derivative of the Ricci curvature to blow up at rate $e^{t/2}$. Uniform $C^k$ bounds for every $k$ hold for the Ricci curvature in the isotrivial case, and for the full Riemann curvature in the torus-fibered case.


10. 对流周期环境中具有非对称核的自由边界SIS模型的长时间动力学与阈值现象

Long-time dynamics and threshold Phenomena for a free-boundary SIS Model with asymmetric kernels in advective periodic environments

作者: Soufiane Bentout, Hoang-Hung Vo

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24368v1

链接: http://arxiv.org/abs/2603.24368v1

摘要: We study a nonlocal SIS epidemic model with free boundaries, advection, and spatial heterogeneity, where the dispersal kernels are not assumed to be symmetric. The model describes the evolution of susceptible and infected populations in a bounded infected habitat whose endpoints move according to nonlocal boundary fluxes. Our goal is to determine the sharp threshold between disease spreading and vanishing, and to characterize the long-time behavior of solutions. The analysis faces several essential difficulties. The linearization around the disease-free equilibrium gives rise to a genuinely coupled nonlocal system with drift, so the relevant spectral quantity cannot be reduced directly to a standard scalar eigenvalue problem. In addition, the presence of advection terms and possibly non-symmetric kernels destroys self-adjointness, so no useful variational characterization is available; in particular, classical Rayleigh quotient and minimax arguments cannot be applied. To overcome these difficulties, we employ the generalized principal eigenvalue theory for nonlocal operators developed by Coville and Hamel, together with the Harnack inequality for non-symmetric nonlocal operators established therein. This non-variational framework is particularly well suited to our setting. Combined with comparison principles, sub- and supersolution constructions, and uniform estimates on time-dependent spatial intervals, it allows us to derive the precise asymptotic behavior of the generalized principal eigenvalue with respect to the spatial domain and the diffusion rate, identify the sharp threshold and the critical habitat size, and determine the long-time dynamics of $S$ and $I$ via an $ω$-limit set approach. To the best of our knowledge, this is the first work on a free-boundary SIS epidemic model with non-symmetric nonlocal dispersal kernels, advection, and spatial periodicity.


11. 三维空间中Pucci算子的主特征值形状优化

Shape Optimization for the Principal Eigenvalue of the Pucci Operator in Three Dimensions

作者: Mohan Mallick, Ram Baran Verma

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24362v1

链接: http://arxiv.org/abs/2603.24362v1

摘要: We investigate shape optimization for the principal eigenvalue of the Pucci extremal operator

$$ \left\{ \begin{aligned} -\mathcal{M}^+_{λ,Λ}(D^{2}u)&=μ^{+}_{1}(Ω)u &&\text{in }Ω,\\ u &=0 &&\text{on }\partialΩ, \end{aligned} \right. $$

in dimension three. Since $\mathcal{M}^+_{λ,Λ}$ is fully nonlinear, in non-divergence form, and non-variational, classical symmetrization and rearrangement methods are not available. We introduce a three-dimensional family of double–pyramidal domains $\{Ω^ω_{γ,a}\}$ parametrized by an anisotropy factor $γ\in \left[\frac{1}{\sqrtω},\sqrtω\right]$ and an affine shear parameter $a\in(-π,π)$, under fixed ellipticity ratio $ω=Λ/λ\ge 1$. Within this family and under a fixed-volume constraint, we prove that the volume-normalized principal eigenvalue is uniquely minimized at the symmetric unsheared configuration $(γ,a)=(1,0)$ among domains in the family $\{Ω^ω_{γ,a}\}$. The proof combines an explicit construction of positive eigenfunctions on seven patches with a lower bound under affine shear deformations. Using the homogeneity and orthogonal invariance of the Pucci operator, we identify an involutive symmetry $γ\mapsto γ^{-1}$ in the associated volume functional and establish strict monotonicity away from the self-dual point $γ=1$. In particular, for $ω>1$, any nontrivial anisotropy or shear strictly increases the normalized principal eigenvalue. This reveals a genuinely three-dimensional rigidity mechanism for a fully nonlinear spectral problem and extends to dimension three the symmetry-minimization phenomenon previously known in the planar case.


12. 分数阶Sobolev空间中的Ciarlet-Nečas条件

Ciarlet Nečas condition in fractional Sobolev spaces

作者: Stanislav Hencl, Jaromír Mielec, Kaushik Mohanta

类别: math.FA, math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24234v1

链接: http://arxiv.org/abs/2603.24234v1

摘要: Let $s\in(\frac{n}{n+1},1)$, $Ω\subset\mathbb{R}^n$ be an open set and let $f\in W^{s,n/s}(Ω,\mathbb{R}^n)$ be mapping with positive distributional Jacobian $\mathcal{J}_f>0$ which models some deformation in fractional Nonlinear Elasticity. We show change of variables formula in this class and as a consequence we show that the analogue of Ciarlet-Nečas condition $\mathcal{J}_f(Ω)=|f(Ω)|$ implies that our mapping is one-to-one a.e.


13. 流形上双重非线性方程的抛物频率

Parabolic Frequency for Doubly Nonlinear Equations on Manifolds

作者: Jin Sun, Philipp Sürig

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24229v1

链接: http://arxiv.org/abs/2603.24229v1

摘要: We establish monotonicity formulas for a parabolic frequency function associated with sign-changing solutions to a class of doubly nonlinear parabolic equations of the form $\partial_t u = \mathcal{L}_{p,\varphi} u^q$ on weighted complete Riemannian manifolds without any curvature assumption, where $\mathcal{L}_{p,\varphi}$ denotes the weighted $p$-Laplacian and $p>1$, $q>0$. As a consequence, we obtain results on backward uniqueness for $q(p-1)\geq 1$ and unique continuation at infinity for $q(p-1) > 1$. We further consider equations with a controlled nonlinear perturbation term and derive an almost-monotonicity formula for the parabolic frequency. By employing the parabolic frequency, we also establish some Liouville-type results for ancient solutions in the case $q(p-1)\geq 1$.


14. 自由间断问题的卷积型泛函的Γ收敛

$Γ$-convergence of convolution-type functionals for free discontinuity problems

作者: Giuseppe Cosma Brusca, Davide Donati, Sergio Scalabrino, Chiara Trifone, Edoardo Voglino

类别: math.AP, math.OC

发布日期: 2026-03-25

arXiv ID: 2603.24192v1

链接: http://arxiv.org/abs/2603.24192v1

摘要: We prove compactness with respect to $Γ$-convergence for a general class of non-local energies modelled after the ones considered in [Gobbino, CPAM (1998)]. We give an integral representation result for the limits, which are free discontinuity functionals defined on the space of generalised special functions of bounded variation. We then characterise the bulk and surface energy densities of the obtained limits by means of minimisation problems on small cubes for the approximating energies.


15. 密度测度

Density Measures

作者: Moritz Schönherr, Friedemann Schuricht

类别: math.AP, math.OC

发布日期: 2026-03-25

arXiv ID: 2603.24163v1

链接: http://arxiv.org/abs/2603.24163v1

摘要: The paper treats density measures as typical examples of finitely additive measures in $\mathbb{R}^n$. We study their structure and derive basic properties. In addition, estimates for related integrals are provided. The results are applied to the precise representative of general integrable functions and then they are specialized to functions of bounded variation. Moreover, a new representation of the generalized gradients in the sense of Clarke is given for the finite dimensional case.


16. 关于联系函数与其分数阶导数阶数的显式公式

On the explicit formula linking a function to the order of its fractional derivative

作者: Vasyl Semenov, Nataliya Vasylyeva

类别: math.AP, math.NA

发布日期: 2026-03-25

arXiv ID: 2603.24149v1

链接: http://arxiv.org/abs/2603.24149v1

摘要: In this paper, given a certain regularity of a function $v$, we derive an explicit formula relating the order $ν_0\in(0,1)$ of the leading fractional derivative in a fractional differential operator $\mathbf{D_t}$ with the variable coefficients $r_i=r_i(x,t)$ and the function $v$ on which this operator acts. Moreover, we discuss application of this result in the reconstruction of the memory order of semilinear subdiffusion with memory terms. To achieve this aim, we analyze some inverse problems to multi-term fractional in time ordinary and partial differential equations with smooth local or nonlocal additional measurements for small time. In conclusion, we discuss how this formula may be exploited to numerical computation of $ν_0$ in the case of discrete noisy observation in the corresponding inverse problems. Our theoretical results along with the computational algorithm are supplemented by numerical tests.


17. 关于无限图上的半线性热方程 II:任意初始数据的爆破现象与全局存在性

On a semilinear heat equation on infinite graphs II: blow-up for arbitrary initial data and global existence

作者: Fabio Punzo, Federico Zucchero

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24112v1

链接: http://arxiv.org/abs/2603.24112v1

摘要: This paper is the second part of the study initiated in a companion work and is devoted to finite-time blow-up and global existence for a semilinear heat equation on infinite weighted graphs. We first establish basic results on mild and classical solutions (which, to the best of our knowledge, were not previously available in the setting of graphs) proving their equivalence under suitable assumptions and showing the existence of a solution between a given sub- and supersolution. We then analyze blow-up and global existence on $\mathbb Z^N$, providing proofs based on methods different from those used on $\mathbb Z^N$ in the existing literature. Moreover, for graphs with positive spectral gap, we prove global existence for small initial data. In contrast with previous functional analytic approaches yielding mild solutions, our method relies on the construction of global-in-time supersolutions and leads to the existence of classical solutions.


18. 关于无限图上的半线性热方程 I:大初始数据下的爆破现象

On a semilinear heat equation on infinite graphs I: blow-up for large initial data

作者: Fabio Punzo, Federico Zucchero

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24110v1

链接: http://arxiv.org/abs/2603.24110v1

摘要: We investigate finite-time blow-up of solutions to the Cauchy problem for a semilinear heat equation posed on infinite graphs. Assuming that the initial datum is sufficiently large, we establish a general blow-up criterion valid on arbitrary infinite graphs. We then apply this result to specific classes of graphs, including trees and the integer lattice. The approach developed in the paper can be regarded as a discrete counterpart of Kaplan’s method, suitably adapted to the graph setting. In a companion paper, which is the second part of this work, we also complement the blow-up analysis by addressing arbitrary initial data and proving global existence for sufficiently small data.


19. 稍微超临界Choquard方程单气泡解的不存在性

Nonexistence of single-bubble solutions for a slightly supercritical Choquard equation

作者: Jinkai Gao

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24100v1

链接: http://arxiv.org/abs/2603.24100v1

摘要: In this paper, we consider the existence of positive solutions to the following slightly supercritical Choquard equation \begin{equation*} \begin{cases} -Δu=\displaystyle\Big(\int\limits_Ω\frac{u^{2^_α+\varepsilon}(y)}{|x-y|^α}dy\Big)u^{2^_α-1+\varepsilon},\quad u>0\ \ &\mbox{in}\ Ω, \quad \ \ u=0 \ \ &\mbox{on}\ \partial Ω, \end{cases} \end{equation*} where $N\geq 3$, $Ω$ is a smooth bounded domain in $\mathbb{R}^{N}$, $α\in (0,N)$, $2^*_α:=\frac{2N-α}{N-2}$ is the upper critical exponent in the sense of Hardy-Littlewood-Sobolev inequality and $\varepsilon>0$ is a small parameter. In contrast with the slightly subcritical Choquard equation studied by Chen and Wang (Calculus of Variations and Partial Differential Equations, 63:235, 2024), we find that there is no chance to construct a family of single-bubble solutions as $\varepsilon\to 0^{+}$.


20. 三维与二维空间中体积保持平均曲率流的最终正则性

Eventual regularity of the volume-preserving mean curvature flow in three and two dimensions

作者: Vedansh Arya, Seongmin Jeon, Vesa Julin

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24091v1

链接: http://arxiv.org/abs/2603.24091v1

摘要: The recent work of Morini-Oronzio-Spadaro and the third author shows that, in three dimensions, a flat-flow solution of the volume-preserving mean curvature flow that converges to a single ball, which is the case for instance when the initial perimeter is less than that of two disjoint balls, converges exponentially fast in Hausdorff distance. In this paper we strengthen this result by proving that after a finite time the flow becomes smooth, satisfies the equation in the classical sense and converges exponentially fast to the limiting ball in every C^k-norm. In the proof we develop a version of Brakke’s epsilon regularity theorem adapted to our setting and derive the necessary nonlinear PDE estimates directly at the level of the discrete minimizing-movement scheme. The same result holds in the planar case.


21. 三维空间中上临界Choquard方程的存在性与渐近性

Existence and asymptotics for the upper critical Choquard equation in dimension three

作者: Jinkai Gao

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24089v1

链接: http://arxiv.org/abs/2603.24089v1

摘要: In this paper, we are interested in the existence and asymptotic behavior of least energy solutions to the upper critical Choquard equation \begin{equation*} \begin{cases} -Δu+au=\displaystyle\left(\int_Ω\frac{u^{6-α}(y)}{|x-y|^α}dy\right)u^{5-α}&\mbox{in}\ Ω, u>0 \ \ &\mbox{in}\ Ω, u=0 \ \ &\mbox{on}\ \partial Ω, \end{cases} \end{equation*} where $Ω\subset \mathbb{R}^{3}$ is a bounded domain with a $C^{2}$ boundary, $α\in (0,3)$, $a \in C(\overlineΩ) \cap C^{1}(Ω)$, and the operator $-Δ+ a$ is coercive. We first establish that the following three properties are equivalent: the existence of least energy solutions, the validity of a strict inequality in the associated minimization problem, and the positivity of the Robin function somewhere in the domain. This leads naturally to the definition of a critical function $a$. Under the perturbation $a \mapsto a + \varepsilon V$ with $a$ critical and $V \in L^{\infty}(Ω)$, we prove that least energy solutions exist. Furthermore, we establish a refined energy estimate and describe their asymptotic profile.


22. 通过非光滑临界点理论研究拟线性椭圆系统的多重性和正则性结果

Multiplicity and Regularity Results for Quasilinear Elliptic Systems via Nonsmooth Critical Point Theory

作者: Simone Mauro

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.24087v1

链接: http://arxiv.org/abs/2603.24087v1

摘要: We study the quasilinear elliptic system

$$ -\textbf{div}(A(x,\boldsymbol u)|D\boldsymbol u|^{p-2}D\boldsymbol u) +\frac{1}{p}\nabla_{\boldsymbol s}A(x,\boldsymbol u)|D\boldsymbol u|^p = \boldsymbol g(x,\boldsymbol u) \quad \text{in } Ω, \qquad \boldsymbol u = 0 \text{ on } \partialΩ, $$

where $p>1$, $Ω\subset\mathbb R^N$ is a bounded domain with $N>1$, and $\boldsymbol g$ satisfies a subcritical growth condition. In this setting, the associated energy functional is, in general, neither differentiable nor locally Lipschitz in the natural Sobolev space. By exploiting a nonsmooth critical point theory, we prove the existence of infinitely many weak solutions by means of an Equivariant Mountain Pass Theorem. In addition, we establish $L^\infty$-bounds for weak solutions by adapting a Moser-type iteration.


23. 二维空间中空间拟周期重力水波的局部适定性

Local well-posedness of spatially quasiperiodic gravity water waves in two dimensions

作者: Mihaela Ifrim, Jon Wilkening, Xinyu Zhao

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.23908v1

链接: http://arxiv.org/abs/2603.23908v1

摘要: We provide the first proof of local well-posedness for the two-dimensional gravity water wave equations with spatially quasi-periodic initial conditions. We represent the solution using holomorphic coordinates, which are equivalent to a conformal mapping formulation of the equations of motion. This allows us to compute the Dirichlet-Neumann operator via the Hilbert transform, which has a simple form in the spatially quasiperiodic setting. We use a Littlewood-Paley decomposition adapted to the quasiperiodic setting and establish multiplicative and commutator estimates in this framework. The key step of the proof is the derivation of quasilinear energy estimates for the linearized water wave equations with quasiperiodic initial data.


24. 次极端赖斯纳-诺德斯特伦黑洞上有质量麦克斯韦方程组的阈值渐近与衰减

Threshold asymptotics and decay for massive Maxwell on subextremal Reissner–Nordström

作者: Bobby Eka Gunara

类别: math.AP, hep-th, math-ph

发布日期: 2026-03-25

arXiv ID: 2603.23905v1

链接: http://arxiv.org/abs/2603.23905v1

摘要: We study the neutral massive Maxwell (Proca) equation on subextremal Reissner–Nordström exteriors. After spherical-harmonic decomposition, the odd sector is scalar, while the even sector remains a genuinely coupled $2\times2$ system. Our starting point is that this even system admits an exact asymptotic polarization splitting at spatial infinity. The three resulting channels carry effective angular momenta $\ell-1$, $\ell$, and $\ell+1$, and these are precisely the indices that govern the late-time thresholds. % For each fixed angular momentum we develop a threshold spectral theory for the cut-off resolvent. We prove meromorphic continuation across the massive branch cut, rule out upper-half-plane modes and threshold resonances, and obtain explicit small- and large-Coulomb expansions for the branch-cut jump. Inverting this jump yields polarization-resolved intermediate tails together with the universal very-late $t^{-5/6}$ branch-cut law. % At the full-field level, high-order angular regularity allows us to sum the modewise leading terms on compact radial sets and obtain a two-regime asymptotic expansion for the radiative branch-cut component of the Proca field, with explicit coefficient fields and quantitative remainders. We also analyze the quasibound resonance branches created by stable timelike trapping, prove residue and reconstruction bounds, and derive a fully self-contained dyadic packet estimate. As a result, the unsplit full Proca field obeys logarithmic compact-region decay, while the radiative branch-cut contribution retains explicit polynomial asymptotics and explicit leading coefficients.


25. 线性化算子的全正性与谱性质

Total positivity and spectral properties of linearized operators

作者: John Albert, Steven Levandosky

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.23876v1

链接: http://arxiv.org/abs/2603.23876v1

摘要: For a class of semilinear elliptic equations, we establish criteria that guarantee that the linearized operator associated with a solution satisfies certain spectral assumptions that are widely used in the analysis of the stability of solitary waves. The criteria only involve the symbol of the linear operator and positivity and symmetry of the solution, and can therefore be verified without an explicit formula for the solution.


26. 混合局部和非局部算子的Choquard方程正解与变号解的存在性

Existence of positive and sign-changing solutions for a Choquard equation involving mixed local and nonlocal operators

作者: Shaoxiong Chen, Hichem Hajaiej, Min Yang, Zhipeng Yang

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.23870v1

链接: http://arxiv.org/abs/2603.23870v1

摘要: We study the Choquard equation involving mixed local and nonlocal operators

$$ -Δu+(-Δ)^{s}u+V(x)u=(\frac{1}{|x|^μ}* F(u))f(u)\quad\text{in }\R^{2}, $$

where $s\in(0,1)$, $μ\in(0,2)$, $F(t)=\int_{0}^{t} f(τ)\,dτ$, and $f$ has subcritical exponential growth of Trudinger–Moser type. Under suitable assumptions on the potential $V$ and the nonlinearity $f$, we prove the existence of a least energy positive solution by a Nehari manifold approach. We also establish the existence of a sign-changing solution by means of invariant sets of descending flow. If, in addition, the nonlinearity is odd, then the problem admits infinitely many sign-changing solutions.


27. 一般无界域中单调型Lotka-Volterra竞争-扩散系统的传播速度

The speeds of propagation for the monostable Lotka-Volterra competition-diffusion system in general unbounded domains

作者: Yang-Yang Yan, Wei-Jie Sheng

类别: math.AP

发布日期: 2026-03-25

arXiv ID: 2603.23834v1

链接: http://arxiv.org/abs/2603.23834v1

摘要: This paper is concerned with the speeds of propagation for the monostable Lotka-Volterra competition-diffusion system in general unbounded domains of $\mathbb{R}^N$. We first establish various definitions of spreading speeds at large time in the situation where one species is an invader and the other is a resident. Then, we study fundamental properties of these new definitions, including their relationships and their dependence on the geometry of the domain and the initial values. Under the conditions that both species possess the same diffusion ability and that the interactions between them are sufficiently weak, we derive an upper bound for the spreading speeds in a large class of domains. Furthermore, we obtain general upper and lower bounds for spreading speeds in exterior domains, as well as a general lower bound in domains containing large half-cylinders. Finally, we construct some particular domains for which the spreading speeds can be zero or infinite.


28. 具有哈迪位势和梯度相关吸收项的椭圆方程:存在性与精细渐近性

Elliptic equations with Hardy potentials and gradient-dependent absorption: existence and refined asymptotics

作者: Florica C. Cîrstea, Maria Fărcăşeanu

类别: math.AP

发布日期: 2026-03-24

arXiv ID: 2603.23771v1

链接: http://arxiv.org/abs/2603.23771v1

摘要: Under sharp conditions, we prove the existence and refined asymptotic behaviour near zero (resp., at infinity) for all positive radial solutions to elliptic equations such as \begin{equation}\label{eq11} \tag{*} \mathbb L_{ρ,λ}(u)=Δu+ (2-N-2ρ), \frac{x\cdot \nabla u}{|x|^2}+ \fracλ{|x|^2}u=|x|^θ,u^q, |\nabla u|^m\quad \mbox{in } Ω\setminus{0}, \end{equation} where $Ω=B_R(0)$ (resp., $Ω=\mathbb R^{N}\setminus B_{1/R}(0)$) for $R>0$ and $N\geq 2$. The dynamics of such solutions is very rich since $ρ, λ,θ\in \mathbb R$ are arbitrary, $ m>0$, $q\geq 0$ and $κ:=m+q-1>0$. To our knowledge, this is the first study of the local properties of the positive solutions of \eqref{eq11} with arbitrary $m>0$ and $λ\not=0$. We identify all profiles near zero (and at infinity via a modified Kelvin transform) under optimal conditions, depending on how $Θ:=(θ+2-m)/κ$ relates to $0$ or the roots $Θ_\pm$ of $t^2+2ρt+λ$ when $λ\leq ρ^2$. For each profile, we advance new methods that unearth the higher order terms in the asymptotic expansion. We highlight two new asymptotic profiles near zero due to the competition between the Hardy potential with $λ>0$ and the gradient-dependent absorption: (i) a blow-up profile $\left[ λ\left( \fracκ{m} \right)^m \right]^{\frac{1}κ} | \log |x||^{\frac{m}κ} $ if $Θ=0$ and (ii) a bounded profile if $Θ<0$. Any radial solution of \eqref{eq11} with $\lim_{r\to 0^+} u(r)=γ\in \mathbb R_+$ satisfies $(P_\pm)$ $u(r)=γ\pm λ^{1/m} γ^{1-κ/m} (1/σ)\, r^σ(1+o(1))$ as $r\to 0^+$, where $σ=-κΘ/m$. For any $γ\in \mathbb R_+$, there is $R>0$ such that \eqref{eq11} has a radial solution (infinitely many) satisfying $(P_-)$ ($(P_+)$).


29. 分数阶Kolmogorov算子的内在Hardy不等式

Intrinsic Hardy inequality for fractional Kolmogorov operator

作者: Damir Kinzebulatov

类别: math.AP, math.FA, math.PR

发布日期: 2026-03-24

arXiv ID: 2603.23621v1

链接: http://arxiv.org/abs/2603.23621v1

摘要: We obtain Hardy inequality for non-local diffusion operator with singular drift, in the case when the strength of attraction to the origin by the drift takes the critical value.