关于丢番图方程D1x^2＋2^mD2=y^n的解数

设Ｄ１、Ｄ２、ｍ、ｘ、ｙ是适合Ｄ１〉１，Ｄ２〉１，２├Ｄ１Ｄ２，ｇｃｄ（Ｄ１，Ｄ２）＝ｇｃｄ（ｘ，ｙ）＝１的正整数，ｎ是适合ｎ├ｈ的奇素数，其中ｈ是虚二次域Ｑ（√－２＾ｍＤ１Ｄ２）的类数。本文主要证明了：方程Ｄ１ｘ＾２＋２＾ｍＤ２＝ｙ＾ｎ至多有５．１０＾１６组例外解（Ｄ１，Ｄ２，ｘ，ｙ，ｍ，ｎ）而且这些解都满足了７≤ｎ〈８．５．１０＾６以及ｙ＾ｎ〈ｅｘｐ（ｅｘｐ（ｅｘｐ４６））。     

q~q±1(q=p~n)的Aurifeuillian分解

ｑｑ±１（ｑ＝ｐｎ）的Ａｕｒｉｆｅｕｉｌｉａｎ分解孙琦洪绍方（四川大学数学系）摘要设素数ｐ≡ε（ｍｏｄ４），其中ε＝１，－１，ｎ为正整数，ｑ＝ｐｎ，ｑ１＝ｑｑ／ｐ，η＝ηｑ＝ｅｘｐ（２πｉ／ｑ）．Φｍ（ｘ）表示ｍ阶分圆多项式．记Ｓε＝Φｑ（εｑ），本...     

素数的判别与分类

素数的判别与分类宋八全（华中师范大学数学系９２级）记ｐ是不等于２，５的素数．本文试用循环小数的性质讨论素数的判别与分类．全文计划如下：（１）建立素数与循环小数的联系，证明一个素数判别定理．（２）确定素数分类关系和制造素数表的方法并指明用此表分解合数．...     

一类表示伪素数的公式

素数最基本的性质是费马小定理，给出了自然数是素数的必要条件：若（p，a）=1（p为素数）则ap-1≡1（modp）．很长一段时间以来，人门认为费马小定理的逆定理也成立，甚至认为n是素数当且仅当2n-1≡1（modn），但这是错误的．1819年萨吕斯（M．Sarrus）证明，2341≡2（mod341），但341＝11×31是合数．后来，人们把满足同余式2n-1≡（modn）的合数叫伪素数．伪素数是否有无穷多？1903年，马洛（Malo）首先证明：如果A是伪素数，2A-1也是伪素数[1].文[2]给出一个伪素数的公式，笔者认为可以给出一类伪素数的公式．现给出预备知识（p为奇素…     

素数个数的估计

素数是数学中最重要、最基本的概念之一．关于素数个数的讨论,早在两千多年前,古希腊学者欧几里得（Ｅｕｃｌｉｄ）已在其名著《几何原本》中给出且证明：素数有无穷多个．人们又发现素数在自然数中所占比例很小,若记π（ｘ）为不超过ｘ的素数个数,数学大师欧拉（Ｌ．Ｅｕｌｅｒ）证明了下面的结论．ｌｉｍｘ→∞π（ｘ）ｘ＝０．然而对于π（ｘ）的估计都经历了极为漫长的过程．１８世纪以前,人们已经知道：在ｎ～２ｎ－２之间（ｎ为自然数）至少有一个素数,在ｎ～２ｎ之间至少有两个素数．利用爱拉托色尼（Ｅｒａｔｏｓｔｈｅｎｅｓ…     

结构不稳定的指数函数

本文讨论了指数函数Ｅλ：ｚ｜→λｅｘｐ（ｚ）的结构不稳定性．     

“mp2型“伪素数的性质与存在

定义 若ｎ是合数,且２ｎ－１＝１（ｍｏｄ ｎ）,则称ｎ是伪素数． 文［１］证得 １０９３２及 ３５１１２这两个数是伪素数,从而否定了陈历功等提出的“伪素数不含平方数因数”的猜想．记ｐ是奇素数,ｍＮ,本文将讨论“ｍＰ２型”伪素数的性质与存在的实例．先引入以下的 引理［２］设使同余式：２ｒ＝１（ｍｏｄ ｍ）成立的最小正整数为ｒ,则 ２ａ＝１（ｍｏｄ ｍ）的充要条件是ｒ（注引理即文［２］第七章定理１的推过２） 定理１ 设ｐ是奇素数,如果ｎ是含有因数Ｐ２的伪素数,则Ｐ２是伪素数． 证明 记ｎ＝ｍｐ２（ｍ Ｎ）,则由伪…     

广义本原指数的缺数系

运用数论和图论技巧，得到了当λ（Ｄ）３时本原有向图Ｄ的广义指数ｅｘｐ（Ｄ，ｋ）的界，这里λ（Ｄ）表示Ｄ中不同长的圈的类数，还证明了对任何整数ｎ，ｔ，不存在ｎ阶本原有向图Ｄ，使得ｎ２－ｔｎ＋１４（ｔ＋１）２＋ｋ－２＜ｅｘｐ（Ｄ，ｋ）＜ｎ２－（ｔ－１）ｎ＋ｔ＋ｋ－３．     

关于丢番图方程 χ^3一У^6=3pz^2的整数解

设p=5（mod 6）为素数．证明了丢番图方程χ^3一У^6=3pz^2。在p=5（mod 12）为素数时均无正整数解;在P=11（mod 12）为素数时均有无穷多组正整数解,并且还获得了该方程全部正整数解的通解公式,同时还给出了该方程的部分整数解．     

稀世珍奇的梅森素数

2009年4月,挪威计算机专家斯特林德莫通过参加一个名为“因特网梅森素数大搜索”（GIMPS）的国际合作项目,发现了第47个梅森素数,该素数为2^42643801-1（即“2的42643801次方减1”）．     

Properties of large prime divisors of numbers of the form p − 1

The main result of this paper is the fact that the fraction of primes p ≤ x satisfying the condition that p ? 1 has a prime divisor q > exp(ln x/ln ln x) and the number of prime divisors of q ? 1 essentially differ from ln ln(x/n), where n = (p ? 1)/q, tends to zero as x increases.     

Distribution of residues and primitive roots

Given an integer N?≥?3, we shall prove that for all primes p?≥?(N???2)²4 ^N , there exists x in (?/p?)^* such that x, x?+?1, ..., x?+?N???1 are all squares (respectively, non-squares) modulo p. Similarly, for an integer N?≥?2, we prove that for all primes $\displaystyle p \geq \exp(2^{5.54N})$ , there exists an element x?∈?(?/p?)^* such that x, x?+?1, ..., x?+?N???1 are all generators of (?/p?)^*.     

Strong Krull primes and flat modules

There are several theorems describing the intricate relationship between flatness and associated primes over commutative Noetherian rings. However, associated primes are known to act badly over non-Noetherian rings, so one needs a suitable replacement. In this paper, we show that the behavior of strong Krull primes most closely resembles that of associated primes over a Noetherian ring. We prove an analogue of a theorem of Epstein and Yao characterizing flat modules in terms of associated primes by replacing them with strong Krull primes. Also, we partly generalize a classical equational theorem regarding flat base change and associated primes in Noetherian rings. That is, when associated primes are replaced by strong Krull primes, we show containment in general and equality in many special cases. One application is of interest over any Noetherian ring of prime characteristic. We also give numerous examples to show that our results fail if other popular generalizations of associated primes are used in place of strong Krull primes.     

Primitive densities of certain sets of primes

While it has already been demonstrated that the set of twin primes (primes that differ by 2) is scarce in the $\text{Σ}\text{1}\text{p}$ (all twin primes) converges whereas $\text{Σ}\text{1}\text{p}$ (all primes) diverges, this paper proves in Theorems 1 and 2 the scarcity of twin primes (and, in general, of primes p which differ by any even integer as well as primes p for which yp + z is prime, y positive, z nonzero, (y, z) = 1) in a novel and natural way — by showing that the natural density of such primes compared to the set of all primes is 0, that is, $\text{lim}{}_{\mathrm{n\to \infty }}\text{(}\text{π′(n)}\text{π(n)}\text{) = 0}$, where π′(n) is the number of, say, twin primes between 1 and n for any n, and π(n) is the number of all primes between 1 and n. Theorem 3 then establishes that if a set of primes is scarce in the sense that the sum of the reciprocals of such primes converges, they are also scarce in the natural density sense outlined above.     

扩张环上的$\Sigma$-相伴素理想

作为对相伴素理想与幂零相伴素理想的推广,我们在本文中引进了$\Sigma$-相伴素理想的定义,探讨了$\Sigma$-相伴素理想的基本性质,证明了Ore扩张环$R[x;\alpha,\delta]$、斜洛朗多项式环$R[x,x^{-1};\alpha]$及斜幂级数环$R[[x;\alpha]]$的$\Sigma$-相伴素理想都分别可以用环$R$的$\Sigma$-相伴素理想来刻画,从而将相伴素理想与幂零相伴素理想的一些已有结论推广到更一般的情形.     

表大偶數為一個不超過三個素數的乘積及一個不超過四個素數的乘積之和

<正> V.Brun最初在1920年證明了:每一充分大的偶數可表為兩個各不超過9個素數的乘積之和.簡記之為(9,9).後來,不少數學家改進與簡化了Brun方法,因此,Brun的結果也得到相應的改進,     

Brauer characters with cyclotomic field of values

It has been shown in an earlier paper [G. Navarro, Pham Huu Tiep, Rational Brauer characters, Math. Ann. 335 (2006) 675-686] that, for any odd prime p, every finite group of even order has a non-trivial rational-valued irreducible p-Brauer character. For p=2 this statement is no longer true. In this paper we determine the possible non-abelian composition factors of finite groups without non-trivial rational-valued irreducible 2-Brauer characters. We also prove that, if p≠q are primes, then any finite group of order divisible by q has a non-trivial irreducible p-Brauer character with values in the cyclotomic field Q(exp(2πi/q)).     

Primes forming arithmetic series and clusters of large primes

By a sieve method and the use of a computer, a search for primes, forming arithmetic series, is reported. The longest series found contained 13 primes.If the local prime density in an interval is unusually large, we say that there is a cluster of primes in the interval. Clusters of large primes are searched for by looking for repetitions of patterns of primes chosen from the beginning of the prime series. The densest large cluster found is 429 983 158 710+11, 13, 17, 19, 23, 37, 41, 43, 47, 53, and 59, with 11 primes out of 49 numbers. The average prime density this high up in the number series is one number only in about 27.     

Ten consecutive primes in arithmetic progression

In 1967 the first set of 6 consecutive primes in arithmetic progression was found. In 1995 the first set of 7 consecutive primes in arithmetic progression was found. Between November, 1997 and March, 1998, we succeeded in finding sets of 8, 9 and 10 consecutive primes in arithmetic progression. This was made possible because of the increase in computer capability and availability, and the ability to obtain computational help via the Internet. Although it is conjectured that there exist arbitrarily long sequences of consecutive primes in arithmetic progression, it is very likely that 10 primes will remain the record for a long time.

     

表大偶數為一個素數及一個不超過四個素數的乘積之和——廣義Riemann猜測下之結果

<正> 引言 本文之目的是在證明作者在[1]內所提及的若干結果,本文所有的結果,均在廣義的Riemann猜測之下,而獲得的. 現在,先將廣義的Riemann猜測述於下: