广义正则平面曲线的顶点

<正> 引言.四顶点定理.自印度加尔各答大学教授 Mukhopadhyaya 证明后,继而论之者颇多.Blaschke 证明:一正则卵形线若与任一圆之交点至多有四点时,则此卵形线至多有四顶点.另一人证明:一正则卵形线若与一圆有2n个交点时,则此卵形线至少有2n个顶点.Fog 及 Graustein 曾推广四顶点定理至简单闭曲线.Jackson 从研究二顶点曲线的特性出发,以研究四顶点曲线,指出了更广泛的四顶点曲线族.因不具二顶点曲线的特性就为四顶点曲线.以上这些曲线是指正则曲线,即曲线上的曲率不仅存     

On curves with special linear systems

Let C be an algebraic curve of genus g. Assume the existence of a g _d ^r , D, on C with r>1 and whose Clifford index e:=d – 2r is near to the Clifford index, c, of C. Here we give criteria for the existence of infinitely many base point free g _e+3 ¹ on C and lower bounds on d and g in terms of r, e and c.     

The Marcinkiewicz-Zygmund inequality with derivatives

Let m≥1 and P be a polynomial of degree at most mn?1. Let dα, dβ be Jacobi distributions and x_kx be zeros of orthogonal polynomials with respect to dα. Then inequality of the type {fx100-1}, is considered.     

每个点都是链回归点的树映射

设f是端点数为n的树T上的连续自映射且T上的每一点都是f的链回归点.本文证明了: (1)如果T的某个端点是f的不动点,那么,T上的每个点都是f的周期为r≤n-1的周期点,或存在自然数r ≤ n-1,使得fr含有湍流; (2)如果f的不动点都在T的内部,那么,T上的每个点都是f的周期为r≤n的周期点,或存在自然数r≤n,使得,fr含有湍流.     

序为(3,3)的正则拟多边形

利用距离正则图的特征值方法,得到如下结论:设Γ是一个有序对为(3,3)正则拟多边形,如果d=r+1,则cd≠1,2,3.     

同伦群和同调群的关系及其应用

<正> 最近几年来,关于同伦群的研究,特别是球面同化群的计算有很大的进步,但是关于更一般的空间的同伦群的计算,就作者所知道的文献来说,似乎没有相应的进展,在这一方面的工作,最早也是最主要的是 Hurewicz 定理,Serre 在[15]中利用所谓 C同构的概念,把 Hurewicz 定理推广到所谓(n-1)维 C 连通空间中,但是也和 Hure-wicz 定理一样,只能讨论 n 维同伦群和 n 维同调群的关系.张素诚,Hilton 及 Barrat     

Galois环上本原序列压缩映射的单性

设Ω是 Ｇａｌｏｉｓ环 ＧＲ（２~ｄ,ｒ）的 Ｔｅｉｃｈｍｕｌｌｅｒ代表集,则 ＧＲ（２~ｄ,ｒ）上每条序列ａ有唯一的权位分解,　其中ａ-ｉ是Ω上序列,同时也可自然视为有限域Ｆ-（２~ｒ）,上序列．设ｆ（ｘ）是环 ＧＲ（２~ｄ,ｒ）上强本原多项式,Ｇ（ｆ（ｘ））表示 ＧＲ（２~ｄ,ｒ）上以ｆ（ｘ）为特征多项式的序列的全体,是Ｆ-（２~ｒ）上一类ｄ－１元多项式, 　本文证明了压缩映射是单射,即对 ａ＝ ｂ当且仅当对所有 ａ,ｂ ∈ Ｇ（ｆ（ｘ））．     

Automorphisms of the Projective Quaternion Unimodular Group of two Dimensions

Let K be the skew field of rational quaternoions.Let R={(a+bi+cj+dk)/2|a,b,c,d =in Z and have the same parity},where Z denotes the ring of rational integers.R is a subring of K and K is the quotient skew field of R. R is usually called the ring of quaternion integers. Let E denote the subgroup of GL_2(R) generated by all elements of the form $[\left( {\begin{array}{*{20}{c}} 1&s\0&1 \end{array}} \right)\]$ and $[\left( {\begin{array}{*{20}{c}} 1&0\t&1 \end{array}} \right)\]$(s,t \in R).Denote the factor groups of GL_2(R) and E modules their centers,both of which are {\pm I},by PGL_2(R) and PE respectively.PE is the commutator subgroup of PGL_2(r). Theorem.Any automorphism of PGL_2(R) (or PE) is one of the following two standard forms $\bar A \mapsto \bar P{\bar A^\sigma }{\bar P^{ - 1}}$ $[A \mapsto \bar P{(\overline {{A^{\tau '}}} )^{ - 1}}{\bar P^{ - 1}}$ where $\bar P \in PGL_2(R)$,\sigma is an automorphism of R and \tau is an anti-automorphism of R.     

若干完全三部图的色唯一性

用P(G,λ)表示图G的色多项式.若对任意图H,当P(H,λ)=P(G,λ)时都有H和G同构,则称图G是色唯一的.给出了以下结果:m≥2且k≥0时,完全三部图K(m,m,m+k)是色唯一的;m≥2且m+1>k≥0时,完全三部图K(m,m+1,m+k)是色唯一的.     

平面凸体的完全不等式组

对于平面凸体，分别用A、p、r、R、d表示它的面积、周长、内径、外径、直径．本文分别给出了其中的三元组合(A，r，R)，(p，r．R)，(p，r，d)，(A，r，d)所满足的不等式，并给出了相应的极值集．     

Maximum Modulus of Polynomials

Let P(z) =n∑j=0 a_jz~j be a polynomial of degree n and let M(P, r) = max|z|=r|P(z)|. If P(z) ≠ 0 in |z| 1, then M( P, r) ≥ ((1 + r)/ (1 + ρ))~ n M( P, ρ).The result is best possible. In this paper we shall present a refinement of this result and some other related results.     

超空间与原空间动力系统之间的关系

设(X,d,f)为拓扑动力系统,其中X为局部紧可分的可度量化空间,d为紧型度量,f为完备映射,用2X表示由X的所有非空闭子集构成的集族,(2X,ρ,2f)为由(X,d,f)所诱导的赋予hit-or-miss拓扑的超空间动力系统.本文引入了余紧点传递和弱拓扑传递的定义.特别的,在X满足一定的条件时,给出了点传递,弱拓扑传递和余紧点传递之间的关系,并研究了(X,d,f)的余紧传递点,回复点和几乎周期点分别与(2X,ρ,2f)的传递点,回复点和几乎周期点之间的蕴含关系.这些结论丰富了赋予hit-or-miss拓扑的超空间的研究内容.     

Geodesic Ham-Sandwich Cuts

Let P be a simple polygon with m vertices, k of which are reflex, and which contains r red points and b blue points in its interior. Let n = m + r + b. A ham-sandwich geodesic is a shortest path in P between two points on the boundary of P that simultaneously bisects the red points and the blue points. We present an O(n log k)-time algorithm for finding a ham-sandwich geodesic. We also show that this algorithm is optimal in the algebraic computation tree model when parameterizing the running time with respect to n and k.     

K3-free图的线图的哈密顿性

设G是一个简单图，Gi G，G1在G中的度定义为d（Gt）=∑v∈v（c）d（v），其中d（v）为v在G中的度数。本文的主要结果是：设G是n≥2阶几乎无桥的简单连通K3-free图，且G≌k1,n-1、Q1和Q2，若对G中任何同构于四个顶点路的导出子图I有d（I）≥n＋2，则G有一个D-闭迹，从而G的线图L（G）是哈密顿图。     

URS' For Weierstrass Products without Exponential Factors

Let $ \cal W $ be the set of entire functions equal to a Weierstrass product of the form $ {f(x)= Ax^q\lim_{r \to \infty} \prod_{|a_j|\leq r}{(1- \fraca {x} {a_j})}} $ where the convergence is uniform in all bounded subsets of $ {\shadC} $ , let $ \cal V $ be the set of $ f\in {\cal W} $ such that $ {\shadC} [\,f]\subset {\cal W} $ , and let $ {\cal H} $ be the $ {\shadC} $ -algebra of entire functions satisfying $ { {\lim_{r\to \infty } } ({\ln M(r,f) / r})=0} $ . Then $ \cal H $ is included in $ {\cal V} $ and strictly contains the set of entire functions of genus zero, (which, itself, strictly contains the $ {\shadC} $ -algebra of entire functions of order 𝜌 < 1). Let $ n, m\in {\shadN} ^* $ satisfy n > m S 3. Let $ a\in {\shadC}^* $ satisfies $ {a^n\not = \fraca{n^n}{(m^m(n-m)^{n-m}})} $ and assume that for every ( n m m )-th root ξ of 1 different from m 1, a satisfies further $ {a^{n}\neq (1+\xi )^{n-m} (\fraca{n^n}{((n-m)^{n-m}m^m}))} $ . Let P ( X ) = X n m aX m + 1 and let T n,m ( a ) be the set of its zeros. Then T n,m ( a ) has n distinct points and is a urs for $ {\cal V} $ . In particular this applies to functions such as sin x and cos x .     

关于Weichsel猜想的一点注记

设P是n-立方体图Q_n的完备控制集．在1994年,Weichsel证明了存在某些整数r_1,r_2,…,r_m使P在Q n中的诱导子图〈P〉为Q_(r1),Q_(r2),…,Q_(rm)的不交之并,并且猜想r_1=r_2=…=r_m．本文证明了当m≤20时,该猜想正确．     

Modules Satisfying the S-Noetherian Property and S-ACCR

Let A = k[x₁,..., x_n] be a standard graded k-algebra over an infinite field k. We assume A is Cohen-Macaulay and has Krull dimension one. Let e denote the multiplicity of A and r - 1 the postulation number of A. Let I be a homogeneous ideal in A of grade one. Let j(I) denote the smallest degree of a regular form in I. Let l (I) denote the smallest power of (x₁,... , x_n) contained in I. If μ(I) denotes the minimum number of generators of I, then we show μ(I) ≤ e + j(I) - max{r,l(I)}, We then show how Dubreil's Second Theorem follows easily from this inequality     

关于广义Thue－Mahler方程的解数

设ａ，ｂ是非零整数，ｐ１，…，ｐｒ是不同的素数，Ｐ＝｛±｜ｍ１，…，ｍｒ是非负整数｝．设Ｋ是ｎ（ｎ≥３）次代数数域，α１，…，αｍ∈ｋ（１＜ｍ＜ｎ），△（α１，…，αｍ）是α１，…，αｍ的判别式，ｆ（ｘ１，…，ｘｍ）＝αＮｋ／Ｑ（α１ｘ１＋…＋αｍｘｍ）∈ｚ［ｘ１，…，ｘｍ］．本文证明了：当ｆ（ｘ１，…，ｘｍ）非退化且Ｐｉ△（α１，…，αｍ）（ｉ＝１，…，ｒ）时，方程ｆ（ｘ１，…，ｘｍ）＝ｂｙ，ｘ１，…，ｘｍ∈ｚ，ｇｃｄ（ｘ１，…，ｘｍ）＝１，ｙ∈Ｐ至多有（４Ｓｄ２）（Ｓｄ）组解（ｘ１，…，ｘｍ，ｙ），其中ｄ＝ｎ！，Ｓ＝ｒ＋ω是ｂ的不同素因数的个数，ｈＡ是Ｋ的类数．     

线性常微分方程组解的特征数的估计

复数域上线性系统ｘ＝Ａ（ｔ）ｘ，当Ａ（ｔ）＝（ａｉｊ（ｔ））ｎ×ｎ具有（ｎ，Ｎ，ｒ） 差异性质且ｒｎ时，解的特征数ｊ有估计λｊ－ｌｉｍｔ→∞１ｔ∫ｔｔ０Ｒｅａｊ（τ）ｄτｎ－１ｒ＋１－ｎｌｉｍｔ→∞１ｔ∫ｔｔ０Ａ（τ）ｄτ，ｊ＝１，２，…，ｎ，其中Ａ（ｔ）＝ｍａｘ｛｜ａｉｊ（ｔ）｜：ｉ，ｊ＝１，２，…，ｎ，ｉ≠ｊ．｝