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1. chinaXiv:202108.00116 [pdf]

Some discussions on Hausdorff metric

黄欢
Subjects: Mathematics >> Mathematics (General)

In this paper, we discuss the properties of functions generated using Hausdorff metric.

submitted time 2021-08-30 Hits386Downloads70 Comment 0

2. chinaXiv:202108.00057 [pdf]

Properties of fuzzy set

黄欢
Subjects: Mathematics >> Mathematics (General)

In this paper, we give some properties related to platform points of a fuzzy set and their applications.

submitted time 2021-08-10 Hits1820Downloads214 Comment 0

3. chinaXiv:202107.00011 [pdf]

Properties of several fuzzy set spaces

Huan Huang
Subjects: Mathematics >> Mathematics (General)

This paper discusses the properties the spaces of fuzzy sets in a metric s- pace equipped with the endograph metric and the sendograph metric, re- spectively. We fist discuss the level characterizations of the Γ-convergence and the endograph metric, and point out the elementary relationships among Γ-convergence, endograph metric and the sendograph metric. On the basis of these results, we present the characterizations of total boundedness, rel- ative compactness and compactness in the space of compact positive α-cuts fuzzy sets equipped with the endograph metric, and in the space of com- pact support fuzzy sets equipped with the sendograph metric, respectively. Furthermore, we give completions of these two kinds of spaces, respectively.

submitted time 2021-08-01 Hits3935Downloads239 Comment 0

4. chinaXiv:202002.00021 [pdf]

关于新型冠状病毒感染人数的预测研究

吴宇宸
Subjects: Mathematics >> Mathematics (General)

2019年12月,新型冠状病毒肺炎(NCP,又称2019-nCoV)疫情从武汉开始爆发,几天内迅速传播到全国乃至海外,对我国的工农业生产和人民生活产生了重要影响。科学有效掌控疫情发展对疫情防控至关重要。本文基于中国卫健委及湖北省卫健委每日公布的累计确诊数,采用逻辑斯蒂模型对数据进行了拟合,以期给该疾病的防控治提供科学依据。通过公布的疫情数据,我们反演了模型的参数,进而有效地模拟了目前疫情的发展,并预测了疫情未来的趋势。我们预测,湖北省疫情还要持续至少2周,而在全国其他地区,疫情可望1周左右达到顶峰。

submitted time 2020-02-18 Hits30350Downloads3204 Comment 0

5. chinaXiv:201809.00178 [pdf]

Regularity for a minimum problem with free boundary in Orlicz spaces

Jun Zheng; Leandro S. Tavares; Claudianor O. Alves
Subjects: Mathematics >> Mathematics (General)

The aim of this paper is to study the heterogeneous optimization problem \begin{align*} \mathcal {J}(u)=\int_{\Omega}(G(|\nabla u|)+qF(u^+)+hu+\lambda_{+}\chi_{\{u>0\}} )\text{d}x\rightarrow\text{min}, \end{align*} in the class of functions $ W^{1,G}(\Omega)$ with $ u-\varphi\in W^{1,G}_{0}(\Omega)$, for a given function $\varphi$, where $W^{1,G}(\Omega)$ is the class of weakly differentiable functions with $\int_{\Omega}G(|\nabla u|)\text{d}x<\infty$. The functions $G$ and $F$ satisfy structural conditions of Lieberman's type that allow for a different behavior at $0$ and at $\infty$. Given functions $q,h$ and constant $\lambda_+\geq 0$, we address several regularities for minimizers of $\mathcal {J}(u)$, including local $C^{1,\alpha}-$, and local Log-Lipschitz continuities for minimizers of $\mathcal {J}(u)$ with $\lambda_+=0$, and $\lambda_+>0$ respectively. We also establish growth rate near the free boundary for each non-negative minimizer of $\mathcal {J}(u)$ with $\lambda_+=0$, and $\lambda_+>0$ respectively. Furthermore, under additional assumption that $F\in C^1([0,+\infty); [0,+\infty))$, local Lipschitz regularity is carried out for non-negative minimizers of $\mathcal {J}(u)$ with $\lambda_{+}>0$.

submitted time 2018-09-23 Hits18205Downloads1569 Comment 0

6. chinaXiv:201809.00180 [pdf]

Regularity in the two-phase free boundary problems under non-standard growth conditions

Jun Zheng
Subjects: Mathematics >> Mathematics (General)

In this paper, we prove several regularity results for the heterogeneous, two-phase free boundary problems $\mathcal {J}_{\gamma}(u)=\int_{\Omega}\big(f(x,\nabla u)+(\lambda_{+}(u^{+})^{\gamma}+\lambda_{-}(u^{-})^{\gamma})+gu\big)\text{d}x\rightarrow \text{min}$ under non-standard growth conditions. Included in such problems are heterogeneous jets and cavities of Prandtl-Batchelor type with $\gamma=0$, chemical reaction problems with $0<\gamma<1$, and obstacle type problems with $\gamma=1$. Our results hold not only in the degenerate case of $p> 2$ for $p-$Laplace equations, but also in the singular case of $1

submitted time 2018-09-22 Hits15507Downloads1407 Comment 0

7. chinaXiv:201809.00179 [pdf]

H\"{o}lder continuity of solutions to the $G$-Laplace equation

Jun Zheng; Yan Zhang
Subjects: Mathematics >> Mathematics (General)

We establish regularity of solutions to the $G$-Laplace equation $-\text{div}\ \bigg(\frac{g(|\nabla u|)}{|\nabla u|}\nabla u\bigg)=\mu$, where $\mu$ is a nonnegative Radon measure satisfying $\mu (B_{r}(x_{0}))\leq Cr^{m}$ for any ball $B_{r}(x_{0})\subset\subset \Omega$ with $r\leq 1$ and $m>n-1-\delta\geq 0$. The function $g(t)$ is supposed to be nonnegative and $C^{1}$-continuous in $[0,+\infty)$, satisfying $g(0)=0$, and for some positive constants $\delta$ and $g_{0}$, $\delta\leq \frac{tg'(t)}{g(t)}\leq g_{0}, \forall t>0$, that generalizes the structural conditions of Ladyzhenskaya-Ural'tseva for an elliptic operator.

submitted time 2018-09-22 Hits995Downloads995 Comment 0

8. chinaXiv:201611.00721 [pdf]

A Note on Elliptic Coordinates

Sun, Che
Subjects: Mathematics >> Mathematics (General)

Explicit equations are obtained to convert Cartesian coordinates to elliptic coordinates, based on which an elliptic-coordinate function can be readily mapped on a uniform Cartesian mesh.Application to Kirchhoff vortex is provided.

submitted time 2018-09-22 Hits39396Downloads2055 Comment 0

9. chinaXiv:201809.00176 [pdf]

一类高阶非线性微分方程Lyapunov不等式

郭旭; 王浩帆; 郑军
Subjects: Mathematics >> Mathematics (General)

本文研究一类高阶非线性微分方程的Lyapunov 不等式,是对《Lyapunov-type inequalities for $\psi$-Laplacian equations》有关结论的进一步探讨和推广.

submitted time 2018-09-18 Hits11124Downloads1470 Comment 0

10. chinaXiv:201809.00116 [pdf]

The obstacle problem for non-coercive equations with lower order term and $L^1-$data

Jun Zheng
Subjects: Mathematics >> Mathematics (General)

The aim of this paper is to study the obstacle problem associated with an elliptic operator having degenerate coercivity, and with a low order term and $L^1-$data. We prove the existence of an entropy solution to the obstacle problem and show its continuous dependence on the $L^{1}-$data in $W^{1,q}(\Omega)$ with some $q>1$.

submitted time 2018-09-13 Hits14671Downloads1256 Comment 0

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