一个包含Euler函数的方程

对任意自然数n≥1,著名的Euler函数ψ(n)定义为不大于n且与n互素的正整数的个数.本文的主要目的是研究方程ψ(ψ(ψ(n)))=2ω(n)的可解性,其中ω(n)表示n的所有不同素因子的个数,并给出了该方程的所有正整数解.     

三类包含Euler函数的方程

讨论了三类包含Euler函数的方程x-ψ(x)=2~(ω(x)),x-ψ(ψ(x))=2~(ω(x))与ψ(x~k)=2~(ω(x~k))的可解性,利用初等方法给出这三类方程的所有正整数解,其中ψ(x)为Euler函数,ω(x)为x的相异素因子个数.     

关于方程φ(abc)=2(φ(a)+φ(b)+φ(c))

设n为任意正整数,φ(n)是Euler函数.主要研究了方程φ(abc)=2(φ(a)+φ(b)+φ(c))的可解性问题,利用数论中的理论和方法,获得了该方程的所有正整数解.     

关于Erds和Ivi的一个问题

令ω(n)表示正整数n的不同素因子的个数,Ω(n)表示正整数n的全部素因子的个数.本文到到了下面两个结果:■     

与Euler函数φ(n)有关的两个方程

设φ(n)是Euler函数.主要研究了方程φ(xy)=k(φ(x)+φ(y))的可解性问题,其中k=4,6,利用初等的方法给出了这2个方程的所有正整数解.     

关于数论函数方程S(SL(n))=φ(n)的可解性

对于任意正整数n,S(n),SL(n),φ(n)分别为Smarandache函数,Smarandache LCM函数和Euler函数.本文利用S(n),SL(n),φ(n)的基本性质结合初等方法推广了方程S(n)=φ(n)和SL(n)=φ(n),研究了方程S(SL(n))=φ(n)的可解性,给出并证明了该方程仅有正整数解n=1,8,9,12,18.     

方程y~2=nx(x~2±1)的正整数解数的上界(英文)

设n是无平方因子正整数.本文利用二次和四次Diophantine方程解数的结果,讨论了方程y~2=nx(x~2±1)的正整数解个数的上界,证明了该方程至多有2~w(n)个正整数解(x,y),其中w(n)是n的不同素因数的个数.     

一种包含欧拉函数Ф（n）的方程

设礼和k为任意正整数,Ф（n）是欧拉函数,Ω（n）表示n的所有素因数的个数．本文的主要目的是利用初等方法研究方程Ф（Ф（n）））^k=2^Ω（n）的可解性,同时获得了该方程的所有正整数解．     

一类包含欧拉函数φ（n）的方程

设m,n为任意正整数,φ（n）是欧拉函数.本文的主要目的是利用初等方法研究方程φ（mn）=k（φ（m）＋φ（n））的可解性,其中k为素数,同时获得了该方程的所有正整数解.     

方程φe（n）= nd（e=1,2,4）的可解性

利用已有的广义欧拉函数的准确计算公式来研究方程φe(n)的可解性,其中n为正整数,d为n的正因子.并利用初等的方法和技巧给出方程φe(n)=n/d(e=1,2,4)的全部正整数解(n,d).     

AF—代数的闭的Jordan理想

讨论AF-代数的闭的Jordan理想。我们证明了AF-代灵敏的一个闭的子集是其一Jordan理想的充分必要条件是它是一个结合理想。     

On the determination of the number of periodic (or closed) solutions of a scalar differential equation with convexity

It is well known that a scalar differential equation , where f(t,x) is continuous, T-periodic in t and weakly convex or concave in x has no, one or two T-periodic solutions or a connected band of T-periodic solutions. The last possibility can be excluded if f(t,x) is strictly convex or concave for some t in the period interval. In this paper we investigate how the actual number of T-periodic solutions for a given equation of this type in principle can be determined, if f(t,x) is also assumed to have a continuous derivative . It turns out that there are three cases. In each of these cases we indicate the monotonicity properties and the domain of values for the function P(ξ)=S(ξ)−ξ, where S(ξ) is the Poincaré successor function. From these informations the actual number of periodic solutions can be determined, since a zero of P(ξ) represents a periodic solution.     

一类拟线性常微分方程的多解

说明一类拟线性特征值问题有两个正解;一个大解,一个小解。同时本也证明小解是一个山路解当参数大时发展成为尖解。     

On a class of nonlinear elliptic equations with fast increasing weight and critical growth

We are concerned with the existence of rapidly decaying solutions for the equation

     

Weak solutions for equations defined by accretive operators II: relaxation limits

In the first part of this paper we define solutions for certain nonlinear equations defined by accretive operators, “dissipative solution”. This kind of solution is equivalent to the viscosity solutions for Hamilton-Jacobi equations and to the entropy solutions for conservation laws.In this paper we use dissipative solutions to obtain several relaxation limits for systems of semilinear transport equations and quasilinear conservation laws. These converge to diffusion second-order equations and in one case to a single conservation law. The relaxation limit is obtained using a version of the perturbed test function method to pass to the limit. This guarantees existence for the considered equations.     

Solutions of the generalized Lennard-Jones system

In this paper, we study solution structures of the following generalized Lennard-Jones system in R~n,x=(-α/|x|~(α+2)+β/|x|~(β+2))x,with 0 α β. Considering periodic solutions with zero angular momentum, we prove that the corresponding problem degenerates to 1-dimensional and possesses infinitely many periodic solutions which must be oscillating line solutions or constant solutions. Considering solutions with non-zero angular momentum, we compute Morse indices of the circular solutions first, and then apply the mountain pass theorem to show the existence of non-circular solutions with non-zero topological degrees. We further prove that besides circular solutions the system possesses in fact countably many periodic solutions with arbitrarily large topological degree, infinitely many quasi-periodic solutions, and infinitely many asymptotic solutions.     

On the existence of bounded noncontinuable solutions

This paper presents necessary and sufficient conditions for an n ‐th order differential equation to have a non‐continuable solution with finite limits of its derivatives up to the order l at the right‐hand end point of the interval of its definition, l ≤ n – 2 (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)