关于分圆域及其最大实子域的类数的上界

设ｍ是适合ｍ≠２（ｍｏｄ４）的正整数，ζｍ是ｍ次本原单位根，又设△ｋ，ｈｍ分别是分圆域Ｋ＝Ｑ（ζｍ）的判别式和类数，本文证明了：当ψ（ｍ）≥２２０时，ｈｍ〈４２３ｗｍＱｍ√△ｋ／（１９．４７）其中ψ（ｍ）是ｍ的Ｅｕｌｅｒ函数ｗｍ是Ｋ中单位根的人数，当ｍ是素数方幂时，Ｑｍ＝１否则Ｑｍ＝２由此可推知：当奇素数Ｐ≥２２３时，ｈｐ〈３６ｐ＾７．５（ｐ／２１．６）＾（ｐ－２）／２     

任意维数的强阻尼非线性波动方程（Ⅰ）—初边值问题

本文研究任意维数的强阻非线性波动方程ｕｔｔ－ａΔｕｔ－Δｕ＝ｆ（ｕ）具第一类齐边界条件的初值问题，设ｆ∈Ｃ＾１，ｆ＾１（ｕ）上方有界，且当ｎ≥４时存在常数Ａ，Ｂ和ｐ，使｜ｆ＾１（ｕ）｜≤Ａ｜ｕ｜＾ｐ＋Ｂ，其中０＜ｐ≤４／（ｎ－４）（ｎ＞４）：０＜ｐ＜∞（ｎ＝４），得到唯一整体强解，从而改进和推广了已知结果。     

样条空间S~μ_k（△）的维数

本文考虑了欧式空间Ｒ￣ｎ中任意单纯形剖分上的样条函数空间．证明了当ｋ≥（３μ＋１）２￣（ｎ－２）＋１时，计算任意单纯形剖分Δ上的ｋ次μ阶光滑样条空间的维数，可归结为计算每个σ－关联域（ｉ－单纯形σ∈Δ）Ｒ（σ）上的２￣（ｎ－ｉ－１）μ次μ阶光滑（ｉ≤ｎ－１）样条空间的维数。这里σ－关联域Ｒ（σ）是指Δ中所有包含σ的单纯形所成的单纯形剖分．     

消失Bergman—Carleson测度和小Bloch空间的特征

本文给出了消失Ｂｅｒｇｍａｎ－Ｃａｒｌｅｓｏｎ测度的一个特征，证明了：当ｆ∈Ｈ（Ｂ），０＜ｐ＜∞时，ｆ∈Ｂ０等价于ｌｉｍ｜ｚ｜→１｜Δｆ（ｚ）｜＝０，等价于ｌｉｍ｜ａ｜→１∫Ｂ｜Δｆ（ｚ）｜ｐＪＲφａ（ｚ）ｄｖ（ｚ）＝０，等价于Δｆ（ｚ）｜ｐｄｖ（ｚ）是消失Ｂｅｒｇｍａｎ－Ｃａｒｌｅｓｏｎ测度．     

关于带宽极值问题的两个结果

本文研究的问题是确定ｅ＊（ｐ,Ｂ）的值,也就是确定顶点数为ｐ、带宽为Ｂ的连通图Ｇ的最小边数,本文给出当Ｂ＝ｐ＋３／２和Ｂ＝ｐ／２＋２时的精确结果。     

二维带形无界区域中Navier－Stokes方程整体吸引子及其维数估计

该文讨论二维无界带形区域中Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程其中Ω＝（０，ｄ）×Ｒ，ｄ＞０为一常数，ｕ与ｐ为未知量，其中ｕ＝（ｕ１，ｕ２）为速度场，ｐ表示压力．我们证明了当ｕ０∈Ｈ，ｆ∈Ｖ且ｆ［ｌｏｇ（ｅ＋｜ｘ｜２）］１／２∈Ｌ２（Ω）时，问题（Ｉ）在Ｈ中存在整体吸引子Ａ，它是的一个子集．对Ａ的Ｈａｕｓｄｏｒｆｆ维数与Ｆｒａｃｔａｌ维数我们也给出了估计．     

Δ—匹配与边面全色数

设Ｇ为Δ（Ｇ）≥５的外平面图且ｘｅｆ（Ｇ）为Ｇ的边面全色数。本文证明了：Δ（Ｇ）≤ｘｅｆ（Ｇ）≤Δ（Ｇ）＋１,且ｘｅｆ（Ｇ）＝Δ（Ｇ）,当且仅当Ｇ含有一个由内边组成且覆盖Ｇ的每一个最大度点的匹配。     

一类有关虚二次域理想类群的指数丢番图方程

设Ｄ１、Ｄ２是适合Ｄ１≥１，Ｄ２〉１，ｇｃｄ（Ｄ１，Ｄ２）＝１的无平方因子正整数，ＩＫ是虚二次域Ｋ＝Ｑ（√－Ｄ１Ｄ２）的理想类群。本文证明了：如果存在正整数ａ、ｂ、ｋ以及奇素数ｐ，可使Ｄ１ａ＾２＋Ｄ２ｂ＾２＝ｋ＾ｐ，ｇｃｄ（ａ，ｂ）＝１，ｂ∈Ｎｐ，２├ｋ，其中Ｎｐ是所有不含２ｔｐ±１之形素因数的正整数的集合，则当ｐ〉５且ｍａｘ（Ｄ１，Ｄ２）≥１０＾１０＾１９７时，ＩＫ必有ｐ阶循环子群。     

自补图中的三角形

该文证明了具有ｐ个顶点的自补图中三角形的数目至多是，当ｐ≡０（Ｍｏｄ４）时为ｐ（ｐ－４）（２ｐ－１）／４８，当ｐ≡１（ｍｏｄ４）时为（ｐ－１）（２ｐ２－７ｐ－３）／４８，并且此二数是最好可能的．     

某些椭圆曲线的L－级数的L（1）的非零性

本文考虑了椭圆曲线Γ＿Ｄ：Ｘ￣３＋Ｙ￣３＝ＤＺ￣３．以ＬＤ（ｓ）记Γ＿Ｄ的ＨｅｃｋｅＬ－级数．由Ｌ＿Ｄ（ｓ）的解析延拓我们将Ｌ＿Ｄ（１）展成有限项之和，然后通过建立ｙ￣２＝ｘ￣３－１６的一个处处有好的约化的模型，证明了当ｐ≡２或５（ｍｏｄ　９）时，Ｌ＿（ｐ￣２）（１）≠０．这些结果是对Ｂｉｒｃｈ和Ｓｗｉｎｎｅｒｆｏｎ－Ｄｙｅｒ猜想的支持。     

非线性椭圆方程自由边值问题球对称解的存在性

给出了如下的非线性椭圆方程自由边值问题-Δu=λu+(1+ε)u+p,x∈B Rn,u|Ω=μ,∫Ωnu=-M(1)在C[0,1]中的球对称解的存在性.并得到比上述问题更一般的非线性椭圆方程自由边值问题-Δu=h(u),x∈B Rn,u|Ω=μ,∫Ωun=-M,在C[0,1]中的球对称解的存在性,其中B为Rn中的单位球,p>1,λ>0,μ<0,M>0,ε>0;λ,μ,M,ε均为常数,n为正整数.     

一个变分不等式的奇异摄动

对变分不等式的奇异摄动问题进行了探索,证明了解的重合集Iε={x∈Ωuε（x)=φ}在Hausdorff距离意义下收敛到ε＝0时解的重合集。     

Improved Approximation for Guarding Simple Galleries from the Perimeter

We provide an O(log?log?opt)-approximation algorithm for the problem of guarding a simple polygon with guards on the perimeter. We first design a polynomial-time algorithm for building ε-nets of size \(O(\frac{1}{\varepsilon}\log\log\frac{1}{\varepsilon})\) for the instances of Hitting Set associated with our guarding problem. We then apply the technique of Brönnimann and Goodrich to build an approximation algorithm from this ε-net finder. Along with a simple polygon P, our algorithm takes as input a finite set of potential guard locations that must include the polygon’s vertices. If a finite set of potential guard locations is not specified, e.g., when guards may be placed anywhere on the perimeter, we use a known discretization technique at the cost of making the algorithm’s running time potentially linear in the ratio between the longest and shortest distances between vertices. Our algorithm is the first to improve upon O(log?opt)-approximation algorithms that use generic net finders for set systems of finite VC-dimension.     

Pluricanonical maps of stable log surfaces

Stable surfaces and their log analogues are the type of varieties naturally occurring as boundary points in moduli spaces. We extend classical results of Kodaira and Bombieri to this more general setting: if (X,Δ)$(X,\mathrm{\Delta })$ is a stable log surface with reduced boundary (possibly empty) and I   is its global index, then 4I(_KX+Δ)$4I(K_X+\mathrm{\Delta })$ is base-point-free and 8I(_KX+Δ)$8I(K_X+\mathrm{\Delta })$ is very ample.     

Indivisibility of Class Numbers of Real Quadratic Fields

Let D denote the fundamental discriminant of a real quadratic field, and let h(D) denote its associated class number. If p is prime, then the Cohen and Lenstra Heuristics give a probability that ph(D). If pgt;3 is prime, then subject to a mild condition, we show that

Blowing Up of Sign-changing Solutions to an Elliptic Subcritical Equation

This paper is concerned with the following non linear elliptic problem involving nearly critical exponent (P^k_ε): (-Δ)^ku=K(x)|u|^{(4k/(n-1k))-ε}u in Ω, Δ^{k-1}u=…=Δu=u=0 on ∂Ω, where Ω is a bounded smooth domain in R^n, n≥ 2k+2, k≥ 1, ε is a small positive parameter and K is a smooth positive function in Ω. We construct signchanging solutions of (P^k_ε) having two bubbles and blowing up either at two different critical points of K with the same speed or at the same critical point.     

The Computational Complexity of the Resultant Method for Solving Polynomial Equations

Under an assumption of distribution on zeros of the polynomials, we have given the estimate of computational cost for the resultant method. The result in that, in probability $1-\mu$, the computational cost of the resultant method for finding $ε$-approximations of all zeros is at most $$cd^2(log d+log\frac{1}{\mu}+loglog\frac{1}ε)$$, where the cost is measured by the number of f-evaluations. The estimate of cost can be decreased to $c(d^2logd+d^2log\frac{1}{\mu}+dloglog\frac{1}ε)$ by combining resultant method with parallel quasi-Newton method.     

图的D(2)点可区别星边色数的一个上界

提出了图的D(β)点可区别星边染色及D(β)点可区别星边色数的概念,并用Lovasz局部引理证明了在β=2时,若G=(V,E)是一个最小度为δ(G)>3的简单无向图,则X_(2-vds)(G)≤24△2/3]。     

自相似集的Hausdorff测度与连续性

对集合F Rn,以dim F和Hdim F(F)分别表示F的Hausdorff维数和dim F维Hausdorff测度.设T=T(f1,...,fm)为Rn中的自相似集,即由相似压缩组成的迭代函数系统{f1...,fm)的吸引子.假如fi(T)∩fj(T)= (i≠j),那么,对任意ε>0,存在δ>0,若D=D(g1,...,gm)为Rn中的自相似集并且sup{||fk(x)-gk(x)||:||x||≤1,1≤k≤m}<δ,则1HdimT(T)-Hdim D(D)|<ε.     

Randomly coloring constant degree graphs

We study a simple Markov chain, known as the Glauber dynamics, for generating a random k ‐coloring of an n ‐vertex graph with maximum degree Δ. We prove that, for every ε > 0, the dynamics converges to a random coloring within O(nlog n) steps assuming k ≥ k₀(ε) and either: (i) k/Δ > α* + ε where α*≈? 1.763 and the girth g ≥ 5, or (ii) k/Δ >β * + ε where β*≈? 1.489 and the girth g ≥ 7. Our work improves upon, and builds on, previous results which have similar restrictions on k/Δ and the minimum girth but also required Δ = Ω (log n). The best known result for general graphs is O(nlog n) mixing time when k/Δ > 2 and O(n²) mixing time when k/Δ > 11/6. Related results of Goldberg et al apply when k/Δ > α* for all Δ ≥ 3 on triangle‐free “neighborhood‐amenable” graphs.© 2012 Wiley Periodicals, Inc. Random Struct. Alg., 2013