THE FUNCTION dk（n） ATCONSECUTIVE INTEGERS

51.IntroductionForallpositiveintegersk32,wedefinethefunctionsdk(n)bytheidentityWeknowthatdk(n)isamultiplicativefunction.Ifthestandardformofnisn=p?'p:'tthenwehavethefollowingformu1aTheaboveformulascanbefoundin[4].Inl984,Heath-Br.wnl2]showedthatforsufficientlylargex,#{nSx'd(n)=d(n 1)}>>x(logx)-'.(1.3)Inl987,Hi1debrand[31improvedthelowerboundto#{n5x:d(n)=d(n 1)}>>x(loglogx)-'.(1.4)Inthispaper5weprovethefollowingresult.Theorem.Smposek(22)isapositiveinteger.FOrsopcientlylarpex,#Ak(x):=#{nS…     

关于丢番图方程（195n）x+（28n）y=（197n）z

运用同余及元素阶的性质,证明了对任意的正整数n,丢番图方程(195n)x+(28n)y=(197n)z仅有正整数解(x, y, z)=(2,2,2)。     

INVOLUTIONS FIXING ^mUi=1 CPi（1） ×HPi（n）＊

Let(M,T) be a closed manifold with an involution T.The fixed point set of T is F.In this article,bordism classes of the involutions with fixed point set F = ∪(from i=1 to m) CP i(1) × HP i(n) are determined,where CP(1) and H P(n) denote the 1-dimensional complex projective space and n-dimensional quaternionic projective space respectively,and n = 2p-2 or n = 2p-1(p > 1).     

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).     

有限生成自由代数FV（LK）（n）的自同构群（英文）

本文研究了自同构群AutLk和AutFV(LK)(n)的结构问题.利用了正交模格及其自同构群的直积分解方法,获得了正交模格Lk和自由代数FV(LK)(n)的自同构群的直积分解式.     

幂级数∑n=0^∞（2n）!／（n!）^2（1／2）^2的收敛性讨论

利用stirling公式和阿拉伯判别法可证级数∑n=0^∞(2n)!/(n!)^2(1/2)^2发散，但其相应的交错级数条件收敛．     

On the Constant Metric Dimension of Generalized Petersen Graphs P（n, 4）

In this paper,we consider the family of generalized Petersen graphs P(n,4).We prove that the metric dimension of P(n,4) is 3 when n ≡ 0(mod 4),and is 4 when n = 4k + 3(k is even).For n ≡ 1,2(mod 4) and n = 4k + 3(k is odd),we prove that the metric dimension of P(n,4) is bounded above by 4.This shows that each graph of the family of generalized Petersen graphs P(n,4)has constant metric dimension.     

On the Maximum Spectral Radius of （m, n）-trees with Given Diameter

Let (V, U) be the vertex-partition of tree T as a bipartite graph. T is called an (m,n)-tree if |V|=m and |U| = n. For given positive integers m,n and d, the maximum spectral radius of all (m,n)-trees on diameter d are obtained, and all extreme graphs are determined.     

SPACELIKE SUBMANIFOLDS IN THE DE SITTER SPACE Sp^（n＋p）（c）WITH CONSTANT SCALAR CURVATURE

Let M^n be a closed spacelike submanifold isometrically immersed in de Sitter space Sp^(n p)(c)， Denote by R,H and S the normalized scalar curvature,the mean curvature and the square of the length of the second fundamental form of M^n ,respectively. Suppose R is constant and R≤c. The pinching problem on S is studied and a rigidity theorem for M^n immersed in Sp^(n p)(c) with parallel normalized mean curvature vector field is proved. When n≥3, the pinching constant is the best. Thus, the mistake of the paper “Space-like hypersurfaces in de Sitter space with constant scalar curvature”(see Manus Math, 1998,95 :499-505) is corrected. Moreover,the reduction of the codimension when M^n is a complete submanifold in Sp^(n p)(c) with parallel normalized mean curvature vector field is investigated.     

n×n非负整数矩阵的极大子群（英文）

In this paper we study the subgroup structure of the semigroup M_n(Z+) of all n × n nonnegative integral matrices under multiplication. We prove that every maximal subgroup of M_n(Z+) containing an idempotent element of rank r is isormorphic to S_r.     

Nearly optimal distributed edge coloring in O(log log n) rounds

An extremely simple distributed randomized algorithm is presented which with high probability properly edge colors a given graph using (1 + ϵ)Δ colors, where Δ is the maximum degree of the graph and ϵ is any given positive constant. The algorithm is very fast. In particular, for graphs with sufficiently large vertex degrees (larger than polylog n, but smaller than any positive power of n), the algorithm requires only O(log log n) communication rounds. The algorithm is inherently distributed, but can be implemented on the PRAM, where it requires O(mΔ) processors and O(log Δ log log n) time, or in a sequential setting, where it requires O(mΔ) time. © 1997 John Wiley & Sons, Inc. Random Struct. Alg., 10, 385–405 (1997)     

INVARIANT TESTS OF EXISTENCE OF THE LINEAR RELATIONSHIP WITH LEFT O(n)-INVARIANT ERRORS

This paper gives the invariant tests of the existence of a linear relationship among row vectors of the mean matrix of the multivariate linear models with the left O(n)-invariant errors. Some asymptotic properties of these testing methods are also discussed.     

An O(n 3 L) potential reduction algorithm for linear programming

We describe a primal-dual potential function for linear programming: $$\phi (x,s) = \rho \ln (x^T s) - \sum\limits_{j = 1}^n {\ln (x_j s_j )} $$ whereρ? n, x is the primal variable, ands is the dual-slack variable. As a result, we develop an interior point algorithm seeking reductions in the potential function with \(\rho = n + \sqrt n \) . Neither tracing the central path nor using the projective transformation, the algorithm converges to the optimal solution set in \(O(\sqrt n L)\) iterations and uses O(n ³ L) total arithmetic operations. We also suggest a practical approach to implementing the algorithm.     

半群OI_n(k)的秩

设OI_n是[n]上的保序严格部分一一变换半群.对任意1≤k≤n-1,研究半群OI_n(k)={α∈OI_n:(■x∈dom(α))x≤k■xα≤k}的秩,证明了半群OI_n(k)的秩为n+1.     

An O(n) algorithm for quadratic knapsack problems

An algorithm is presented which solves bounded quadratic optimization problems with n variables and one linear constraint in at most O(n) steps. The algorithm is based on a parametric approach combined with well-known ideas for constructing efficient algorithms. It improves an O(n log n) algorithm which has been developed for a more restricted case of the problem.     

Gauge Orbit Types for Theories with Gauge Group O(n), SO(n) or Sp(n)

We determine the orbit types of the action of the group of local gauge transformations on the space of connections in a principal bundle with structure group O(n), SO(n) or Sp(n) over a closed, simply connected manifold of dimension 4. On the way we derive a classification of Howe subgroups of SO(n) up to conjugacy.     

An algorithm for linear programming which requires O(((m+n)n 2+(m+n)1.5 n)L) arithmetic operations

We present an algorithm for linear programming which requires O(((m+n)n ²+(m+n)^1.5 n)L) arithmetic operations wherem is the number of constraints, andn is the number of variables. Each operation is performed to a precision of O(L) bits.L is bounded by the number of bits in the input. The worst-case running time of the algorithm is better than that of Karmarkar's algorithm by a factor of .     

A hybrid algorithm for finding thekth smallest ofn elements in O(n) time

The problem of finding thekth smallest ofn elements can be solved either with O(n) algorithms or with O(n ²) algorithms. Although they require a higher number of operations in the worst case, O(n ²) algorithms are generally preferred to O(n) algorithms because of their better average performance. We present a hybrid algorithm which is O(n) in the worst case and efficient in the average case.     

An O(n) Algorithm for Projecting a Vector on the Intersection of a Hyperplane and a Box in Rn

We consider the problem of projecting a vector on the intersection of a hyperplane and a box in Rⁿ. This paper extends a previous result of Maculan, Minoux, and Plateau (Ref. 1) concerning the projection of a vector on the intersection of a hyperplane and Rⁿ ₊. We present an O(n) time algorithm based on the linear-time median-finding algorithm. This algorithm determines the median of the components of the vector to be projected. Computational results are also presented in order to evaluate the algorithm and its time complexity. We consider two sets of instances which are randomly generated for any given n. The algorithm was successful in solving all the instances in a reasonable time.