A Remark on Chen’s Theorem (Ⅱ)

Let p denote a prime and P2 denote an almost prime with at most two prime factors. The author proves that for suffciently large x,sum from p≤x p 2=P2 1>(1.13Cx)/(log~2x), where the constant 1.13 constitutes an improvement of the previous result 1.104 due to J. Wu.     

A Remark on Chen''''s Theorem (Ⅱ)

Let p denote a prime and P2 denote an almost prime with at most two prime factors. The author proves that for sufficiently large x,∑ρ≤хр 2＝P21 ＞1.13Cx/log2x, where the constant 1.13 constitutes an improvement of the previous result 1.104 due to J. Wu.     

一个数论函数的倒数和

Let p(n) denote the largest prime factor of an integer n≥2, and let Q(n) denote the largest prime power which divides n≥2. The purpose of this paper is to give asymptotic formula for the sum.     

The Distribution of K-full Integers Ⅱ

Let k≥2 be a fixed integer.A natural number n is called k-full, if p~k|nwhenever p is a prime factor of n.Let A_k(x) denote the number of k-full inte-gers not exceeding x. A.Ivic proved on the Lindelof hypothesis     

本刊英文版2009年52卷第5期摘要

Let p be the set of prime numbers and P（n） denote the largest prime factor of integer n 〉 1. Write
C3 = （p1p2p3 ： pi ∈P （i = 1,2,3）, pi ≠ pj （i ≠ j）},
B3 = （p1p2p3 ： pi ∈ P（ i = 1,2,3）, p1 = p2 or p1 = p3 or p2 = P3, but not p1= p2 = p3}.     

A NOTE ON A TRANSFERENCE THEOREM OF THE SYSTEMS OF LINEAR CONGRUENCES

<正> Let p be a prime number. Let a_(ij)(1≤i≤t,1≤j≤s) be a set of st integers.Weuse the notations x=max(1, |x|), p_1=[(p-1)/2], p_2=[p/2], and (a)_p to denote the integer satisfying (a)_p=a(mod p),-p_1≤(a)_p≤p_2. Consider the dual of linear congruences     

On the Number of Solutions of the Congruence X_1~2 +…+X_k~2≡0 (modp) with 1≤x_1<…

乐茂华 《数学进展》1991,(2)

On the inverse problem relative to dynamics of the ω function

Let P be the set of prime numbers and P (n) denote the largest prime factor of integer n > 1. Write C3 = {p1p2p3 : pi ∈ P (i = 1, 2, 3), pi = pj (i = j)}, B3 = {p1p2p3 : pi ∈ P (i = 1, 2, 3), p1 = p2 or p1 = p3 or p2 = p3, but not p1 = p2 = p3}. For n = p1p2p3 ∈ C3 ∪ B3, we define the w function by ω(n) = P (p1 + p2)P (p1 + p3)P (p2 + p3). If there is m ∈ S - C3 ∪ B3 such that ω(m) = n, then we call m S-parent of n. We shall prove that there are infinitely many elements of C3 which have enough C3-parents an...     

The estimate for mean values on prime numbers relative to \frac{4} {p} = \frac{1} {{n_1 }} + \frac{1} {{n_2 }} + \frac{1} {{n_3 }}

If n is a positive integer,let f （n） denote the number of positive integer solutions （n 1,n 2,n 3） of the Diophantine equation 4/n=1/n₁ + 1/n₂ + 1/n₃.For the prime number p,f （p） can be split into f 1 （p） + f 2 （p）,where f i （p） （i=1,2） counts those solutions with exactly i of denominators n 1,n 2,n 3 divisible by p.In this paper,we shall study the estimate for mean values ∑ p相似文献   

Congruent elliptic curves with non-trivial Shafarevich-Tate groups: Distribution part

Given a large positive number x and a positive integer k, we denote by Qk(x) the set of congruent elliptic curves E(n): y2= z3- n2 z with positive square-free integers n x congruent to one modulo eight,having k prime factors and each prime factor congruent to one modulo four. We obtain the asymptotic formula for the number of congruent elliptic curves E(n)∈ Qk(x) with Mordell-Weil ranks zero and 2-primary part of Shafarevich-Tate groups isomorphic to(Z/2Z)2. We also get a lower bound for the number of E(n)∈ Qk(x)with Mordell-Weil ranks zero and 2-primary part of Shafarevich-Tate groups isomorphic to(Z/2Z)4. The key ingredient of the proof of these results is an independence property of residue symbols. This property roughly says that the number of positive square-free integers n x with k prime factors and residue symbols(quadratic and quartic) among its prime factors being given compatible values does not depend on the actual values.     

On the density of shifted primes with large prime factors

As usual, denote by P(n) the largest prime factor of the integer n 1 with the convention P(1) = 1.For 0 θ 1, define Tθ(x) := |{p x : P(p-1) ≥ p~θ}|.In this paper, we obtain a new lower bound for Tθ(x) as x →∞, which improves some recent results of Luca et al.(2015) and Chen and Chen(2017). As a corollary, we partially prove a conjecture of Chen and Chen(2017)about the size of Tθ(x).     

On the Number of Conjugacy Classes in Semi-Products of Certain Finite Groups

Let V be a vector space of n-dimension over the field GF(p) of p elements,where p is a prime. V is also an elementary abelian p-group.Let G be a p'-group oflinear transformations on V.Theorem 1 Let π_v(a_1,a_2) be the number of the common fixed points of a_1and a_2 on V, a_1, a_2 ∈G. Let k(GV) be the number of conjugacy classes in thesemi-product GV (We also denote it by GV) of G and V. Then     

关于有限域上一类方程解的个数

Let Fq be a finite field with q = pf elements,where p is an odd prime.Let N(a1x12 + ···+anxn2 = bx1 ···xs) denote the number of solutions(x1,...,xn) of the equation a1x12 +···+ anxn2 = bx1 ···xs in Fnq,where n 5,s n,and ai ∈ F*q,b ∈ F*q.In this paper,we solve the problem which the present authors mentioned in an earlier paper,and obtain a reduction formula for the number of solutions of equation a1x21 + ··· + anxn2 = bx1 ···xs,where n 5,3 ≤ s n,under a certain restriction on coefficients.We also obtain an explicit formula for the number of solutions of equation a1x21 + ··· + anxn2 = bx1 ···xn-1 in Fqn under a restriction on n and q.     

On reducible Heegaard splittings

Let V∪S W be a reducible Heegaard splitting of genus g = g(S)≥2.For a maximal prime connected sum decomposition of V∪S W,let q denote the number of the genus 1 Heegaard splittings of S2×S1 in the decomposition,and p the number of all other prime factors in the decomposition.The main result of the present paper is to describe the relation of p,q and dim(C V∩CW).     

Explicit Formulae for Values of Dedekind Zeta Functions of Two Kinds of Cyclotomic Fields

Let K = Q(m) denote the m-th cyclotomic field, and K+ its maximal real subfield, where m =exp is an m-th primary root of unity. Let K (s) denote the Dedekind zeta function ofK. For prime integers m = p, Fumio Hazama recently in [1] obtained formulae for calculating special values of K(s) and K+(s), i.e., calculating formulae of K+(1 - n) and for positive integers n, which are the newest results of a series of his work in many years (see [1-3]).Here we develop Hazama's work for prime integ…     

关于同余式$\sigma(n)\equiv 1\pmod n$, II

Let k ≥ 2 be an integer, and let a（n） denote the sum of the positive divisors of an integer n. We call n a quasi-multiperfect number if a（n） = kn ＋ 1. In this paper, we give some necessary properties of quasi-multiperfect numbers with four different prime divisors.     

On the Congruence σ(n) ≡ 1(mod n), II

Let k ≥ 2 be an integer, and let σ(n) denote the sum of the positive divisors of an integer n. We call n a quasi-multiperfect number if σ(n) = kn + 1. In this paper, we give some necessary properties of quasi-multiperfect numbers with four different prime divisors.     

Recognition of the Projective Special Linear Group over GF（3）

Let P be a finite group and denote by w（P） the set of its element orders. P is called k-recognizable by the set of its element orders if for any finte group G with ω（G） =ω（P） there are, up to isomorphism, k finite groups G such that G ≌P. In this paper we will prove that the group Lp（3）, where p 〉 3 is a prime number, is at most 2-recognizable.     

子群的S-条件置换性对有限群结构的影响

Let G be a finite group. Fix a prime divisor p of IGI and a Sylow p-subgroup P of G, let d be the smallest generator number of P and Ma（P） denote a family of maximal subgroups P1, P2 , Pd of P satisfying ∩^di=1 Pi = Ф（P）, the Frattini subgroup of P. In this paper, we shall investigate the influence of s-conditional permutability of the members of some fixed .Md（P） on the structure of finite groups. Some new results are obtained and some known results are generalized.     

关于商高数的Je\'{s}manowicz猜想

Let(a, b, c) be a primitive Pythagorean triple. Je′smanowicz conjectured in 1956 that for any positive integer n, the Diophantine equation(an)x+(bn)y=(cn)z has only the positive integer solution(x, y, z) =(2, 2, 2). Let p ≡ 3(mod 4) be a prime and s be some positive integer. In the paper, we show that the conjecture is true when(a, b, c) =(4p2s-1, 4p s, 4p2s+ 1) and certain divisibility conditions are satisfied.