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Fast Tabulation of Challenge Pseudoprimes Andrew Shallue and Jonathan Webster
THE OPEN BOOK SERIES 2 ANTS XIII Proceedings of the Thirteenth Algorithmic Number Theory Symposium Fast tabulation of challenge pseudoprimes Andrew Shallue and Jonathan Webster msp THE OPEN BOOK SERIES 2 (2019) Thirteenth Algorithmic Number Theory Symposium msp dx.doi.org/10.2140/obs.2019.2.411 Fast tabulation of challenge pseudoprimes Andrew Shallue and Jonathan Webster We provide a new algorithm for tabulating composite numbers which are pseudoprimes to both a Fermat test and a Lucas test. Our algorithm is optimized for parameter choices that minimize the occurrence of pseudoprimes, and for pseudoprimes with a fixed number of prime factors. Using this, we have confirmed that there are no PSW-challenge pseudoprimes with two or three prime factors up to 280. In the case where one is tabulating challenge pseudoprimes with a fixed number of prime factors, we prove our algorithm gives an unconditional asymptotic improvement over previous methods. 1. Introduction Pomerance, Selfridge, and Wagstaff famously offered $620 for a composite n that satisfies (1) 2n 1 1 .mod n/ so n is a base-2 Fermat pseudoprime, Á (2) .5 n/ 1 so n is not a square modulo 5, and j D (3) Fn 1 0 .mod n/ so n is a Fibonacci pseudoprime, C Á or to prove that no such n exists. We call composites that satisfy these conditions PSW-challenge pseudo- primes. In[PSW80] they credit R. Baillie with the discovery that combining a Fermat test with a Lucas test (with a certain specific parameter choice) makes for an especially effective primality test[BW80]. -
Pseudoprime Reductions of Elliptic Curves
Mathematical Proceedings of the Cambridge Philosophical Society VOL. 146 MAY 2009 PART 3 Math. Proc. Camb. Phil. Soc. (2009), 146, 513 c 2008 Cambridge Philosophical Society 513 doi:10.1017/S0305004108001758 Printed in the United Kingdom First published online 14 July 2008 Pseudoprime reductions of elliptic curves BY ALINA CARMEN COJOCARU Dept. of Mathematics, Statistics and Computer Science, University of Illinois at Chicago, Chicago, IL, 60607-7045, U.S.A. and The Institute of Mathematics of the Romanian Academy, Bucharest, Romania. e-mail: [email protected] FLORIAN LUCA Instituto de Matematicas,´ Universidad Nacional Autonoma´ de Mexico,´ C.P. 58089, Morelia, Michoacan,´ Mexico.´ e-mail: [email protected] AND IGOR E. SHPARLINSKI Dept. of Computing, Macquarie University, Sydney, NSW 2109, Australia. e-mail: [email protected] (Received 10 April 2007; revised 25 April 2008) Abstract Let b 2 be an integer and let E/Q be a fixed elliptic curve. In this paper, we estimate the number of primes p x such that the number of points n E (p) on the reduction of E modulo p is a base b prime or pseudoprime. In particular, we improve previously known bounds which applied only to prime values of n E (p). 1. Introduction Let b 2 be an integer. Recall that a pseudoprime to base b is a composite positive integer m such that the congruence bm ≡ b (mod m) holds. The question of the distri- bution of pseudoprimes in certain sequences of positive integers has received some in- terest. For example, in [PoRo], van der Poorten and Rotkiewicz show that any arithmetic 514 A. -
Prime Divisors in the Rationality Condition for Odd Perfect Numbers
Aid#59330/Preprints/2019-09-10/www.mathjobs.org RFSC 04-01 Revised The Prime Divisors in the Rationality Condition for Odd Perfect Numbers Simon Davis Research Foundation of Southern California 8861 Villa La Jolla Drive #13595 La Jolla, CA 92037 Abstract. It is sufficient to prove that there is an excess of prime factors in the product of repunits with odd prime bases defined by the sum of divisors of the integer N = (4k + 4m+1 ℓ 2αi 1) i=1 qi to establish that there do not exist any odd integers with equality (4k+1)4m+2−1 between σ(N) and 2N. The existence of distinct prime divisors in the repunits 4k , 2α +1 Q q i −1 i , i = 1,...,ℓ, in σ(N) follows from a theorem on the primitive divisors of the Lucas qi−1 sequences and the square root of the product of 2(4k + 1), and the sequence of repunits will not be rational unless the primes are matched. Minimization of the number of prime divisors in σ(N) yields an infinite set of repunits of increasing magnitude or prime equations with no integer solutions. MSC: 11D61, 11K65 Keywords: prime divisors, rationality condition 1. Introduction While even perfect numbers were known to be given by 2p−1(2p − 1), for 2p − 1 prime, the universality of this result led to the the problem of characterizing any other possible types of perfect numbers. It was suggested initially by Descartes that it was not likely that odd integers could be perfect numbers [13]. After the work of de Bessy [3], Euler proved σ(N) that the condition = 2, where σ(N) = d|N d is the sum-of-divisors function, N d integer 4m+1 2α1 2αℓ restricted odd integers to have the form (4kP+ 1) q1 ...qℓ , with 4k + 1, q1,...,qℓ prime [18], and further, that there might exist no set of prime bases such that the perfect number condition was satisfied. -
Abstract in This Paper, D-Strong and Almost D-Strong Near-Rings Ha
Periodica Mathematica Hungarlca Vol. 17 (1), (1986), pp. 13--20 D-STRONG AND ALMOST D-STRONG NEAR-RINGS A. K. GOYAL (Udaipur) Abstract In this paper, D-strong and almost D-strong near-rings have been defined. It has been proved that if R is a D-strong S-near ring, then prime ideals, strictly prime ideals and completely prime ideals coincide. Also if R is a D-strong near-ring with iden- tity, then every maximal right ideal becomes a maximal ideal and moreover every 2- primitive near-ring becomes a near-field. Several properties, chain conditions and structure theorems have also been discussed. Introduction In this paper, we have generalized some of the results obtained for rings by Wong [12]. Corresponding to the prime and strictly prime ideals in near-rings, we have defined D-strong and almost D-strong near-rings. It has been shown that a regular near-ring having all idempotents central in R is a D-strong and hence almost D-strong near-ring. If R is a D-strong S-near ring, then it has been shown that prime ideals, strictly prime ideals and com- pletely prime ideals coincide and g(R) = H(R) ~ ~(R), where H(R) is the intersection of all strictly prime ideals of R. Also if R is a D-strong near-ring with identity, then every maximal right ideal becomes a maximal ideal and moreover every 2-primitive near-ring becomes a near-field. Some structure theorems have also been discussed. Preliminaries Throughout R will denote a zero-symmetric left near-ring, i.e., R -- Ro in the sense of Pilz [10]. -
[Math.NT] 10 May 2005
Journal de Th´eorie des Nombres de Bordeaux 00 (XXXX), 000–000 Restriction theory of the Selberg sieve, with applications par Ben GREEN et Terence TAO Resum´ e.´ Le crible de Selberg fournit des majorants pour cer- taines suites arithm´etiques, comme les nombres premiers et les nombres premiers jumeaux. Nous demontrons un th´eor`eme de restriction L2-Lp pour les majorants de ce type. Comme ap- plication imm´ediate, nous consid´erons l’estimation des sommes exponentielles sur les k-uplets premiers. Soient les entiers posi- tifs a1,...,ak et b1,...,bk. Ecrit h(θ) := n∈X e(nθ), ou X est l’ensemble de tous n 6 N tel que tousP les nombres a1n + b1,...,akn+bk sont premiers. Nous obtenons les bornes sup´erieures pour h p T , p > 2, qui sont (en supposant la v´erit´ede la con- k kL ( ) jecture de Hardy et Littlewood sur les k-uplets premiers) d’ordre de magnitude correct. Une autre application est la suivante. En utilisant les th´eor`emes de Chen et de Roth et un «principe de transf´erence », nous demontrons qu’il existe une infinit´ede suites arithm´etiques p1 < p2 < p3 de nombres premiers, telles que cha- cun pi + 2 est premier ou un produit de deux nombres premier. Abstract. The Selberg sieve provides majorants for certain arith- metic sequences, such as the primes and the twin primes. We prove an L2–Lp restriction theorem for majorants of this type. An im- mediate application is to the estimation of exponential sums over prime k-tuples. -
FACTORING COMPOSITES TESTING PRIMES Amin Witno
WON Series in Discrete Mathematics and Modern Algebra Volume 3 FACTORING COMPOSITES TESTING PRIMES Amin Witno Preface These notes were used for the lectures in Math 472 (Computational Number Theory) at Philadelphia University, Jordan.1 The module was aborted in 2012, and since then this last edition has been preserved and updated only for minor corrections. Outline notes are more like a revision. No student is expected to fully benefit from these notes unless they have regularly attended the lectures. 1 The RSA Cryptosystem Sensitive messages, when transferred over the internet, need to be encrypted, i.e., changed into a secret code in such a way that only the intended receiver who has the secret key is able to read it. It is common that alphabetical characters are converted to their numerical ASCII equivalents before they are encrypted, hence the coded message will look like integer strings. The RSA algorithm is an encryption-decryption process which is widely employed today. In practice, the encryption key can be made public, and doing so will not risk the security of the system. This feature is a characteristic of the so-called public-key cryptosystem. Ali selects two distinct primes p and q which are very large, over a hundred digits each. He computes n = pq, ϕ = (p − 1)(q − 1), and determines a rather small number e which will serve as the encryption key, making sure that e has no common factor with ϕ. He then chooses another integer d < n satisfying de % ϕ = 1; This d is his decryption key. When all is ready, Ali gives to Beth the pair (n; e) and keeps the rest secret. -
Recent Progress in Additive Prime Number Theory
Introduction Arithmetic progressions Other linear patterns Recent progress in additive prime number theory Terence Tao University of California, Los Angeles Mahler Lecture Series Terence Tao Recent progress in additive prime number theory Introduction Arithmetic progressions Other linear patterns Additive prime number theory Additive prime number theory is the study of additive patterns in the prime numbers 2; 3; 5; 7;:::. Examples of additive patterns include twins p; p + 2, arithmetic progressions a; a + r;:::; a + (k − 1)r, and prime gaps pn+1 − pn. Many open problems regarding these patterns still remain, but there has been some recent progress in some directions. Terence Tao Recent progress in additive prime number theory Random models for the primes Introduction Sieve theory Arithmetic progressions Szemerédi’s theorem Other linear patterns Putting it together Long arithmetic progressions in the primes I’ll first discuss a theorem of Ben Green and myself from 2004: Theorem: The primes contain arbitrarily long arithmetic progressions. Terence Tao Recent progress in additive prime number theory Random models for the primes Introduction Sieve theory Arithmetic progressions Szemerédi’s theorem Other linear patterns Putting it together It was previously established by van der Corput (1929) that the primes contained infinitely many progressions of length three. In 1981, Heath-Brown showed that there are infinitely many progressions of length four, in which three elements are prime and the fourth is an almost prime (the product of at most -
A Member of the Order of Minims, Was a Philosopher, Mathematician, and Scientist Who Wrote on Music, Mechanics, and Optics
ON THE FORM OF MERSENNE NUMBERS PREDRAG TERZICH Abstract. We present a theorem concerning the form of Mersenne p numbers , Mp = 2 − 1 , where p > 3 . We also discuss a closed form expression which links prime numbers and natural logarithms . 1. Introduction. The friar Marin Mersenne (1588 − 1648), a member of the order of Minims, was a philosopher, mathematician, and scientist who wrote on music, mechanics, and optics . A Mersenne number is a number of p the form Mp = 2 − 1 where p is an integer , however many authors prefer to define a Mersenne number as a number of the above form but with p restricted to prime values . In this paper we shall use the second definition . Because the tests for Mersenne primes are relatively simple, the record largest known prime number has almost always been a Mersenne prime . 2. A theorem and closed form expression Theorem 2.1. Every Mersenne number Mp , (p > 3) is a number of the form 6 · k · p + 1 for some odd possitive integer k . Proof. In order to prove this we shall use following theorems : Theorem 2.2. The simultaneous congruences n ≡ n1 (mod m1) , n ≡ n2 (mod m2), .... ,n ≡ nk (mod mk) are only solvable when ni = nj (mod gcd(mi; mj)) , for all i and j . i 6= j . The solution is unique modulo lcm(m1; m2; ··· ; mk) . Proof. For proof see [1] Theorem 2.3. If p is a prime number, then for any integer a : ap ≡ a (mod p) . Date: January 4 , 2012. 1 2 PREDRAG TERZICH Proof. -
New Formulas for Semi-Primes. Testing, Counting and Identification
New Formulas for Semi-Primes. Testing, Counting and Identification of the nth and next Semi-Primes Issam Kaddouraa, Samih Abdul-Nabib, Khadija Al-Akhrassa aDepartment of Mathematics, school of arts and sciences bDepartment of computers and communications engineering, Lebanese International University, Beirut, Lebanon Abstract In this paper we give a new semiprimality test and we construct a new formula for π(2)(N), the function that counts the number of semiprimes not exceeding a given number N. We also present new formulas to identify the nth semiprime and the next semiprime to a given number. The new formulas are based on the knowledge of the primes less than or equal to the cube roots 3 of N : P , P ....P 3 √N. 1 2 π( √N) ≤ Keywords: prime, semiprime, nth semiprime, next semiprime 1. Introduction Securing data remains a concern for every individual and every organiza- tion on the globe. In telecommunication, cryptography is one of the studies that permits the secure transfer of information [1] over the Internet. Prime numbers have special properties that make them of fundamental importance in cryptography. The core of the Internet security is based on protocols, such arXiv:1608.05405v1 [math.NT] 17 Aug 2016 as SSL and TSL [2] released in 1994 and persist as the basis for securing dif- ferent aspects of today’s Internet [3]. The Rivest-Shamir-Adleman encryption method [4], released in 1978, uses asymmetric keys for exchanging data. A secret key Sk and a public key Pk are generated by the recipient with the following property: A message enciphered Email addresses: [email protected] (Issam Kaddoura), [email protected] (Samih Abdul-Nabi) 1 by Pk can only be deciphered by Sk and vice versa. -
The Pseudoprimes to 25 • 109
MATHEMATICS OF COMPUTATION, VOLUME 35, NUMBER 151 JULY 1980, PAGES 1003-1026 The Pseudoprimes to 25 • 109 By Carl Pomerance, J. L. Selfridge and Samuel S. Wagstaff, Jr. Abstract. The odd composite n < 25 • 10 such that 2n_1 = 1 (mod n) have been determined and their distribution tabulated. We investigate the properties of three special types of pseudoprimes: Euler pseudoprimes, strong pseudoprimes, and Car- michael numbers. The theoretical upper bound and the heuristic lower bound due to Erdös for the counting function of the Carmichael numbers are both sharpened. Several new quick tests for primality are proposed, including some which combine pseudoprimes with Lucas sequences. 1. Introduction. According to Fermat's "Little Theorem", if p is prime and (a, p) = 1, then ap~1 = 1 (mod p). This theorem provides a "test" for primality which is very often correct: Given a large odd integer p, choose some a satisfying 1 <a <p - 1 and compute ap~1 (mod p). If ap~1 pi (mod p), then p is certainly composite. If ap~l = 1 (mod p), then p is probably prime. Odd composite numbers n for which (1) a"_1 = l (mod«) are called pseudoprimes to base a (psp(a)). (For simplicity, a can be any positive in- teger in this definition. We could let a be negative with little additional work. In the last 15 years, some authors have used pseudoprime (base a) to mean any number n > 1 satisfying (1), whether composite or prime.) It is well known that for each base a, there are infinitely many pseudoprimes to base a. -
Neural Networks and the Search for a Quadratic Residue Detector
Neural Networks and the Search for a Quadratic Residue Detector Michael Potter∗ Leon Reznik∗ Stanisław Radziszowski∗ [email protected] [email protected] [email protected] ∗ Department of Computer Science Rochester Institute of Technology Rochester, NY 14623 Abstract—This paper investigates the feasibility of employing This paper investigates the possibility of employing ANNs artificial neural network techniques for solving fundamental in the search for a solution to the quadratic residues (QR) cryptography problems, taking quadratic residue detection problem, which is defined as follows: as an example. The problem of quadratic residue detection Suppose that you have two integers a and b. Then a is is one which is well known in both number theory and a quadratic residue of b if and only if the following two cryptography. While it garners less attention than problems conditions hold: [1] such as factoring or discrete logarithms, it is similar in both 1) The greatest common divisor of a and b is 1, and difficulty and importance. No polynomial–time algorithm is 2) There exists an integer c such that c2 ≡ a (mod b). currently known to the public by which the quadratic residue status of one number modulo another may be determined. This The first condition is satisfied automatically so long as ∗ work leverages machine learning algorithms in an attempt to a 2 Zb . There is, however, no known polynomial–time (in create a detector capable of solving instances of the problem the number of bits of a and b) algorithm for determining more efficiently. A variety of neural networks, currently at the whether the second condition is satisfied. -
On Sufficient Conditions for the Existence of Twin Values in Sieves
On Sufficient Conditions for the Existence of Twin Values in Sieves over the Natural Numbers by Luke Szramowski Submitted in Partial Fulfillment of the Requirements For the Degree of Masters of Science in the Mathematics Program Youngstown State University May, 2020 On Sufficient Conditions for the Existence of Twin Values in Sieves over the Natural Numbers Luke Szramowski I hereby release this thesis to the public. I understand that this thesis will be made available from the OhioLINK ETD Center and the Maag Library Circulation Desk for public access. I also authorize the University or other individuals to make copies of this thesis as needed for scholarly research. Signature: Luke Szramowski, Student Date Approvals: Dr. Eric Wingler, Thesis Advisor Date Dr. Thomas Wakefield, Committee Member Date Dr. Thomas Madsen, Committee Member Date Dr. Salvador A. Sanders, Dean of Graduate Studies Date Abstract For many years, a major question in sieve theory has been determining whether or not a sieve produces infinitely many values which are exactly two apart. In this paper, we will discuss a new result in sieve theory, which will give sufficient conditions for the existence of values which are exactly two apart. We will also show a direct application of this theorem on an existing sieve as well as detailing attempts to apply the theorem to the Sieve of Eratosthenes. iii Contents 1 Introduction 1 2 Preliminary Material 1 3 Sieves 5 3.1 The Sieve of Eratosthenes . 5 3.2 The Block Sieve . 9 3.3 The Finite Block Sieve . 12 3.4 The Sieve of Joseph Flavius .