具非局部源的非线性高阶抛物型方程解的全局存在性与非全局存在性（英文）

本文考虑一类具非局部源的高阶抛物型方程u_t=-(-Δ)^mu+(∫_Rⁿ|u|^1+σdy)⁽(p-1)/(1+σ))|u|^r的Cauchy问题.近年来,我们已给出这一方程的Fujita临界指标p_c=1+((2m-n(r-1))(1+σ))/(nσ),即当1 c时,对任意初值,解都在有限时刻发生爆破;当p> p_c时,存在非全局解也存在全局解,这取决于初值的大小.本文进一步确定了这一方程的第二临界指标a^*=(2m+(n(p-1))/(1+σ))/(p+r-2),用于在p>p_c这一全局解与非全局解的共存区域内鉴别初值的大小.我们发现:(1)与具局部源|u|^p的高阶抛物型方程的第二临界指标a^*=2/(p-m)不同的是,这里与空间维数n有关;(2)非局部源中参数σ的增大有...     

非线性规划中一个梯度投影法的收敛性质

我们考虑非线性规划问题(P)■f(x),其中R={x|Ax=a,Bx≤b},A是p×n矩阵,其秩为p,B是q×n矩阵,x∈E~n,a∈E~p,b∈E~q,f(x)∈C~1.我们以R~*表示(P)的最优解集合,并假定R非空.最近,M.S.Bazaraa与J.J.Goode     

一类具有非局部扩散的时滞Lotka-Volterra竞争模型的行波解

本文研究一类具有非局部扩散的时滞Lotka-Volterra竞争模型{(δ)/(δ)t u1(x,t)=d1 [(J1*u1)(x,t)-u1(x,t)]+r1u1(x,t)[1 - a1u1(x,t)- b1u1(x,t-Τ1)-c1u2(x,t-Τ2)],(δ)/(δ)tu2(x,t)=d2[(J2*u2)(x,t)-u2(x,t)]+r2u2(x,t)[1 - a2u2(x,t)- b2u2(x,t -Τ3)-c2u1(x,t-Τ4)]行波解的存在性问题.通过利用交叉迭代技巧,我们可以把行波解的存在性转化为寻找一对适当的上下解,这篇文章中的结果推广了已有的一些结果.     

奇异半线性非局部反应扩散方程Cauchy问题局部解的存在性

本文讨论如下初值问题局部解的存在性 u/ t- (1/ tσ)Δu =(∫RNuλ(t,y) dy) p /λur + f (x) ,t>0 ,x∈ RNlimt→ 0 + u(t,x ) =0 ,　　　　　　　　　　　　　 x∈ RN其中σ>0 ,λ≥ 1,p≥ 0 ,r≥ 1,p+ r>1,f (x)连续有界非负但不恒等于零 ,Δ是 N维 L aplace算子 ,所得结论推广了文献 [2 ,3]的相应结果     

带磁场多临界非局部椭圆问题的多解

该文考虑下列带磁场的多临界非局部椭圆方程■多解的存在性,其中Ω是R^N中带光滑边界的有界区域,N≥4,i是虚数单位,2_s~*=(N+α_s)/(N-2),N-4<α_s 0并且2≤p <2~*=2N/(N-2).假定磁向量位势A(x)=(A₁(x),A₂ (x),…,A_N(x))取实值并且满足局部H?lder连续.该文利用Ljusternik-Schnirelman理论证明了当λ较小时,方程(0.1)至少有cat_Ω(Ω)个非平凡解.     

含临界指数的拟线性椭圆系统正对称解的存在性（英文）

本文讨论一类拟线性椭圆型系统-Δpu=μ|u|p-2 u|x|p+2αQ(x)(α+β)|x|s|u|α-2 u|v|β+σ1|u|q1-2 u,x∈Ω,-Δpv=μ|v|p-2v|x|p+2βQ(x)(α+β)|x|s|u|α|v|β-2v+σ2|v|q2-2v,x∈Ω,u=v=0,x∈Ω,其中Δpu=div(|▽u|p-2▽u)是p-Laplacian,2≤pN,ΩRN是一个有界光滑区域,0∈Ω,且Ω关于O(N)的一个闭子群G对称,0≤μ,=((N-p)/p)p,σ1,σ2≥0,0≤sp,α,β1满足α+β=p*(s)=(N-s)p/(N-p),pq1,q2p*=Np/(N-p),Q(x)是Ω上的连续G对称函数.应用Palais对称临界原理和变分方法,我们建立了该系统几个全新的正G-对称解的存在性结果.     

数形结合 另解一道数学竞赛题

<正>2017年全国初中数学邀请赛第11题:已知二次函数y=x²+2mx-3m+1,自变量x及实数p、q满足4p2+2mx-3m+1,自变量x及实数p、q满足4p²+9q2+9q²=2,1/2x+3pq=1,且y的最小值为1.求m的值.解由1/2x+3pq=1可得x+6pq=2,即2p×3q=2-x.∵4p2=2,1/2x+3pq=1,且y的最小值为1.求m的值.解由1/2x+3pq=1可得x+6pq=2,即2p×3q=2-x.∵4p²+9q2+9q²=2,∴4p2=2,∴4p²+2×2p×3q+9q2+2×2p×3q+9q²=2+2×(2-x)=6-2x,即(2p+3q)2=2+2×(2-x)=6-2x,即(2p+3q)²=6-2x.     

R~N上临界增长p-Kirchhoff型方程的非平凡解的存在性

本文主要研究以下具临界增长的非线性p-Kirchhoff型方程的非平凡解的存在性:{-(a+b∫_(R~N)|▽u|~p)?_pu=|u|~(p*-2)u+μf (x)|u|~(q-2)u, x∈R~N,(0.1) u∈D~(1,p)(R~N),其中a≥0,b0,1pN,1qp,p*=N_p/(N-p),μ≥0,?_pu=div(|▽u|~(p-2)▽u)表示p-Laplace算子对函数u的作用, f∈L(p*/(p*-q))(R~N)\{0}且f是非负的.本文利用Ekeland变分原理和山路定理证明方程(0.1)在适当条件下至少存在两个非平凡解.     

一类共形不变摄动积分方程正解的存在性

本文讨论了一类共形不变摄动积分方程正解的存在性. 我们证明了:当参数对(p, q) 属于集合(-n, 0) × (0,∞) 且pq + p + 2n = 0 时, 对应摄动积分方程存在正解; 而当参数对(p, q) 属于集合(0,∞)×(-∞, 0) 也满足pq +p+2n = 0 时, 摄动积分方程不存在非负解. 这与原共形不变积分方程有着本质的不同, 此结果隐含着这类积分方程正解的存在性取决于解在无穷远处的性态.     

巧解两则

巧解1解方程: 1+3一J l十3了 解原方程变形为 即3一j=3, 故原方程的解为二 3j·3一J+3一x 1十3工 一x一1, -一1. 巧解2 sr=Zy=10万 已知x,y,z是不为零的实数,且 ,求生+生一兰的值. X yZ 解注意到5火2~10,设SJ一2,一10了一k (k)O且k笋1.) 5火2- l1 一k丁,2二k;,10= k鲁 11 k丁·k丁 且p、夸+告一*导 则0,=k2︸2 1 .1 —十一 Xy 故 1 .12 —十—一— X yZ (责审余炯沛)巧解两则@任根保$河南省济源市第一中学!454650~~…     

Global Existence and Blow-up for a Parabolic System with Nonlinear Boundary Conditions

This paper deals with the global existence and blow-up of positive solutions to the systems: u_t = ∇(u^∇u) + u¹ + v^a v_t = ∇(v^n∇v) + u^b + v^k in B_R × (0, T) \frac{∂u}{∂η} = u^αv^p, \frac{∂v}{∂η} = u^qv^β on S_R × (0, T) u(x, 0) = u_0(x), v(x, 0} = v_0(x) in B_R We prove that there exists a global classical positive solution if and only if l ≤ l, k ≤ 1, m + α ≤ 1, n + β ≤ 1, pq ≤ (1 - m - α)(1 - n - β),ab ≤ 1, qa ≤ (1 - n - β) and pb ≤ (1 - m - α).     

Global blow-up for a heat system with localized sources and absorptions

In this paper there are established the global existence and finite time blow-up results of nonnegative solution for the following parabolic systemut=Δu vp(x0, t)-aur, x∈Ω, t＞0,vt=Δv uq(x0,t)-bvs, x∈Ω, t＞0subject to homogeneous Dirichlet conditions and nonnegative initial data, where x0 ∈Ω is a fixed point, p, q, r, s ≥ 1 and a, b ＞ 0 are constants. In the situation when nonnegative solution (u, v) of the above problem blows up in finite time, it is showed that the blow-up is global and this differs from the local sources case. Moreover, for the special case r = s = 1,are obtained uniformly on compact subsets of Ω, where T* is the blow-up time.     

二阶拟线性微分方程组边值问题的三个对称正解

本文讨论二阶拟线性微分方程组边值问题( p(x'))'+a(t),(t,x,y)=0,( q(y'))'+b(t)g(t,x,y)=0,x(0)-B0(x'(0))=x(1)+Bo(x'(1))=0,y(0)-B1(y'(0))=y(1)+B1(y'(1))=0,其中f,g是非负连续的函数.利用五个泛函的不动点定理,赋予f和g一些增长条件保证至少三个对称正解的存在性.     

Multiple Positive Solutions for a Nonlinear Elliptic Equation Involving Hardy–Sobolev–Maz'ya Term

In this paper, we study the existence and nonexistence of multiple positive solutions for the following problem involving Hardy–Sobolev–Maz'ya term:-Δu- λu/|y|2=|u|pt-1u/|y|t+ μf(x), x ∈Ω,where Ω is a bounded domain in RN(N ≥ 2), 0 ∈Ω, x =(y, z) ∈ Rk× RN-kand pt =N +2-2t N-2(0 ≤ t ≤2). For f(x) ∈ C1(Ω)\{0}, we show that there exists a constant μ* 0 such that the problem possessesat least two positive solutions if μ∈(0, μ*) and at least one positive solution if μ = μ*. Furthermore,there are no positive solutions if μ∈(μ*, +∞).     

Blow Up of Solutions to One Dimensional Initial-boundary Value Problems for Semilinear Wave Equations with Variable Coefficients

This paper is devoted to studying the following initial-boundary value problemfor one-dimensional semilinearwave equationswith variable coefficients andwith subcritical exponent: $u_{tt}-∂_x(a(x)∂_xu)=|u|^p, x > 0, t > 0, n=1,$ where $u=u(x,t)$ is a real-valued scalar unknown function in $[0,+∞)×[0,+∞)$, here a(x) is a smooth real-valued function of the variable $x∈(0,+∞)$. The exponents p satisfies $1 < p < +∞$ in (0.1). It is well-known that the number $p_c(1)=+∞$ is the critical exponent of the semilinear wave equation (0.1) in one space dimension (see for e.g., [1]). We will establish a blowup result for the above initial-boundary value problem, it is proved that there can be no global solutions no matter how small the initial data are, and also we give the lifespan estimate of solutions for above problem.     

非线性Neumann问题正解的存在性

研究非线性Neumann问题(p(t)u′)′+q(t)u=f(t,u),t∈(0,1),u′(0)=u′(1)=0正解的存在性,其中p,q∈C[0,1]满足p(t)>0,0*,t∈[0,1],b*,t∈[0,1],b^*为线性问题(p(t)u′)′+bu=0,u′(0)=0,u(1)=0的第一特征值.运用拓扑度理论及Rabinowitz全局分歧定理为上述问题建立了正解的存在性结果.     

一类带临界Sobolev指数及有拟超临界Neumann边界条件的椭圆方程正解的多重性

本文讨论了Ω上如下一类带临界增长的椭圆方程在拟超临界的Neumann边界条件下正解的存在性:-Div(| u |p-2 u) =λum up*-1,-| u |p-2 u ν=ψ(x)uq-1,x∈Ω,x∈Ω.这里Ω∈RN,(N≥3)是光滑有界区域, 1≤p < N,0< m < p-1,(N -1)pN - p= p*N-1 ≤q < p*,其中p* =NpN - p是W1,p(Ω)→Ls(Ω)的Sobolev临界指数,p*N-1 =(N -1)pN - p是W1,p(Ω)→Lt( Ω)的在(N-1)维流形上的临界指数,λ>0是一个正参数.     

出现在双色谱中的非线性双曲型守恒律组整体光滑解的存在性(英文)

本文讨论了出现在双色谱中的非线性双曲型守恒律组的如下Cauchy问题{ut+(u/1+u+v)x=0,vt+(v/1+u+v)x=0,初值为u(x,0)=u0(x),v(x,0)=v0(x)的整体光滑解的存在性和唯一性.分析过程基于对角化方法和特征线法.     

一类奇异拟线性椭圆方程正解的多重性

研究奇异拟线性椭圆型方程{-div(|x|~(-ap)|▽u|~(p-2)▽u) + f(x)|u|~(p-2) = g(x)\u|~(q-2)u + λh(x)|u|~(r-2),x R~N,u(x) 0,x∈ R~N,其中λ0是参数,1pN(N3),1rpgp*=0a(N—p)/p,p*=Np/{N~pd),aa+l,d=a+l-60,权函数f(x),g(x),h(x)满足一定的条件.利用山路引理和Ekeland变分原理证明了问题至少有两个非平凡的弱解.     

REGULARITY RESULTS FOR SOME QUASI-LINEAR ELLIPTIC SYSTEMS INVOLVING CRITICAL EXPONENTS

The authors show the regularity of weak solutions for some typical quasi-linear elliptic systems governed by two p-Laplacian operators. The weak solutions of the following problem with lack of compactness are proved to be regular when α(x) and α,β,p, q satisfy some conditions: where Ω(?) RN (N≥3) is a smooth bounded domain.