scholarly journals Rigidity and non-recurrence along sequences

2013 ◽  
Vol 34 (5) ◽  
pp. 1464-1502 ◽  
Author(s):  
V. BERGELSON ◽  
A. DEL JUNCO ◽  
M. LEMAŃCZYK ◽  
J. ROSENBLATT
Keyword(s):  
Dynamical System ◽  
Continued Fraction ◽  
Finite Measure ◽  
Ergodic System ◽  
Recurrent Sequence ◽  
Continued Fraction Expansion ◽  
Weakly Mixing ◽  
Positive Integers

AbstractWe study two properties of a finite measure-preserving dynamical system and a given sequence $({n}_{m} )$ of positive integers, namely rigidity and non-recurrence. Our goal is to find conditions on the sequence which ensure that it is, or is not, a rigid sequence or a non-recurrent sequence for some weakly mixing system or more generally for some ergodic system. The main focus is on weakly mixing systems. For example, we show that for any integer $a\geq 2$ the sequence ${n}_{m} = {a}^{m} $ is a sequence of rigidity for some weakly mixing system. We show the same for the sequence of denominators of the convergents in the continued fraction expansion of any irrational $\alpha $. We also consider the stronger property of IP-rigidity. We show that if $({n}_{m} )$ grows fast enough then there is a weakly mixing system which is IP-rigid along $({n}_{m} )$ and non-recurrent along $({n}_{m} + 1)$.

RELATION BETWEEN A CLASS OF QUASIPERIODIC LATTICES GENERATED BY THE SUBSTITUTION METHOD AND THE GENERALIZED CONTINUED FRACTION EXPANSION

1996 ◽  
Vol 10 (17) ◽  
pp. 2081-2101
Author(s):  
TOSHIO YOSHIKAWA ◽  
KAZUMOTO IGUCHI
Keyword(s):  
Continued Fraction ◽  
Positive Real Number ◽  
Real Numbers ◽  
Continued Fraction Expansion ◽  
Positive Real ◽  
Periodic Sequences ◽  
One Dimensional ◽  
Finite Period ◽  
The One ◽  
Positive Integers

The continued fraction expansion for a positive real number is generalized to that for a set of positive real numbers. For arbitrary integer n≥2, this generalized continued fraction expansion generates (n−1) sequences of positive integers {ak}, {bk}, … , {yk} from a given set of (n−1) positive real numbers α, β, …ψ. The sequences {ak}, {bk}, … ,{yk} determine a sequence of substitutions Sk: A → Aak Bbk…Yyk Z, B → A, C → B,…,Z → Y, which constructs a one-dimensional quasiperiodic lattice with n elements A, B, … , Z. If {ak}, {bk}, … , {yk} are infinite periodic sequences with an identical period, then the ratio between the numbers of n elements A, B, … , Z in the lattice becomes a : β : … : ψ : 1. Thereby the correspondence is established between all the sets of (n−1) positive real numbers represented by a periodic generalized continued fraction expansion and all the one-dimensional quasiperiodic lattices with n elements generated by a sequence of substitutions with a finite period.

scholarly journals Good approximation and characterization of subgroups of R = Z

2001 ◽  
Vol 38 (1-4) ◽  
pp. 97-113 ◽  
Author(s):  
A. Bíró ◽  
J. M. Deshouillers ◽  
Vera T. Sós
Keyword(s):  
Continued Fraction ◽  
Irrational Number ◽  
Explicit Construction ◽  
Continued Fraction Expansion ◽  
Open Problems ◽  
Positive Integers

Let be a real irrational number and A =(xn) be a sequence of positive integers. We call A a characterizing sequence of or of the group Z mod 1 if lim n 2A n !1 k k =0 if and only if 2 Z mod 1. In the present paper we prove the existence of such characterizing sequences, also for more general subgroups of R = Z . Inthespecialcase Z mod 1 we give explicit construction of a characterizing sequence in terms of the continued fraction expansion of. Further, we also prove some results concerning the growth and gap properties of such sequences. Finally, we formulate some open problems.

Some properties of the continued fraction expansion of (m/n) e1/q

1970 ◽  
Vol 67 (1) ◽  
pp. 67-74 ◽  
Author(s):  
K. R. Matthews ◽  
R. F. C. Walters
Keyword(s):  
Continued Fractions ◽  
Continued Fraction ◽  
Continued Fraction Expansion ◽  
Image Position ◽  
Positive Integers

Introduction. Continued fractions of the form are called Hurwitzian if b1, …, bh, are positive integers, ƒ1(x), …, ƒk(x) are polynomials with rational coefficients which take positive integral values for x = 0, 1, 2, …, and at least one of the polynomials is not constant. f1(x), …, fk(x) are said to form a quasi-period.

scholarly journals On the metrical theory of a non-regular continued fraction expansion

2015 ◽  
Vol 23 (2) ◽  
pp. 147-160
Author(s):  
Dan Lascu ◽  
George Cîrlig
Keyword(s):  
Dynamical System ◽  
Continued Fraction ◽  
Probability Function ◽  
Transition Probability ◽  
Continued Fraction Expansion ◽  
Metrical Theory ◽  
Unilateral Shift ◽  
Symbolic Dynamical System ◽  
Continued Fraction Expansions ◽  
Transition Probability Function

Abstract We introduced a new continued fraction expansions in our previous paper. For these expansions, we show the Brodén-Borel-Lévy type formula. Furthermore, we compute the transition probability function from this and the symbolic dynamical system of the natural number with the unilateral shift.

On the Lower Range of Perron's Modular Function

1969 ◽  
Vol 21 ◽  
pp. 808-816 ◽  
Author(s):  
J. R. Kinney ◽  
T. S. Pitcher
Keyword(s):  
Finite Number ◽  
Continued Fraction ◽  
Modular Function ◽  
Finite Collection ◽  
Continued Fraction Expansion ◽  
Lower Range ◽  
Image Position ◽  
Positive Integers

The modular function Mwas introduced by Perron in (6). M(ξ) (for irrational ξ) is denned by the property that the inequalityis satisfied by an infinity of relatively prime pairs (p, q)for positive d,but by at most a finite number of such pairs for negative d.We will writefor the continued fraction expansion of ξ ∈ (0, 1) and for any finite collection y1,…, ykof positive integers we will writeIt is known (see 6) thatWhere

A NEW POINT IN LAGRANGE SPECTRUM

2012 ◽  
Vol 09 (02) ◽  
pp. 393-403
Author(s):  
K. C. PRASAD ◽  
HRISHIKESH MAHATO ◽  
SUDHIR MISHRA
Keyword(s):  
Continued Fraction ◽  
Infinite Sequence ◽  
Cluster Point ◽  
Continued Fraction Expansion ◽  
Irrational Numbers ◽  
Lagrange Spectrum ◽  
Positive Integers

Let I denote the set of all irrational numbers, θ ∈ I, and simple continued fraction expansion of θ be [a0, a1, …, an, …]. Then a0 is an integer and {an}n≥1 is an infinite sequence of positive integers. Let Mn(θ) = [0, an, an-1, …, a1] + [an+1, an+2, …]. Then the set of numbers { lim sup Mn(θ) ∣ θ ∈ I} is called the Lagrange Spectrum 𝔏. Notably 3 is the first cluster point of 𝔏. Essentially lim inf 𝔏 or [Formula: see text]. Perron [Über die approximation irrationaler Zahlen durch rationale, I, S.-B. Heidelberg Akad. Wiss., Abh. 4 (1921) 17 pp; Über die approximation irrationaler Zahlen durch rationale, II, S.-B. Heidelberg Akad. Wiss., Abh.8 (1921) 12 pp.] has found that lim inf { lim sup Mn(θ) ∣ θ = [a0, a1, a2, …, an, …] and [Formula: see text]. This article forwards the value of lim inf{lim sup Mn(θ) ∣ θ = [a0, a1, …, an, …] and an ≥ 4 frequently}, a long awaited cluster point of Lagrange Spectrum.

scholarly journals A Note on Continued Fractions

1960 ◽  
Vol 12 ◽  
pp. 303-308 ◽  
Author(s):  
A. Oppenheim
Keyword(s):  
Real Number ◽  
Continued Fractions ◽  
Continued Fraction ◽  
Continued Fraction Expansion ◽  
Quadratic Irrational ◽  
Image Position ◽  
Positive Integers ◽  
Periodic Continued Fractions

Any real number y leads to a continued fraction of the type(1)where ai, bi are integers which satisfy the inequalities(2)by means of the algorithm(3)the a's being assigned positive integers. The process terminates for rational y; the last denominator bk satisfying bk ≥ ak + 1. For irrational y, the process does not terminate. For a preassigned set of numerators ai ≥ 1, this C.F. development of y is unique; its value being y.Bankier and Leighton (1) call such fractions (1), which satisfy (2), proper continued fractions. Among other questions, they studied the problem of expanding quadratic surds in periodic continued fractions. They state that “it is well-known that not only does every periodic regular continued fraction represent a quadratic irrational, but the regular continued fraction expansion of a quadratic irrational is periodic.

scholarly journals Metrical properties of best approximants

1992 ◽  
Vol 53 (1) ◽  
pp. 78-91
Author(s):  
Jos Blom
Keyword(s):  
Rational Number ◽  
Continued Fraction ◽  
Irrational Number ◽  
Main Tool ◽  
Rational Numbers ◽  
Two Dimensional ◽  
Ergodic System ◽  
Continued Fraction Expansion

AbstractA rational number is called a best approximant of the irrational number ζ if it lies closer to ζ than all rational numbers with a smaller denominator. Metrical properties of these best approximants are studied. The main tool is the two-dimensional ergodic system, underlying the continued fraction expansion.

On the Continued Fraction Expansion of Fixed Period in Finite Fields

2015 ◽  
Vol 58 (4) ◽  
pp. 704-712 ◽  
Author(s):  
Hela Benamar ◽  
Amara Chandoul ◽  
M. Mkaouar
Keyword(s):  
Lower Bound ◽  
Positive Integer ◽  
Finite Fields ◽  
Continued Fraction ◽  
Period Length ◽  
Continued Fraction Expansion ◽  
Positive Integers ◽  
Fixed Period

AbstractThe Chowla conjecture states that if t is any given positive integer, there are infinitely many prime positive integers N such that Per() = t, where Per() is the period length of the continued fraction expansion for . C. Friesen proved that, for any k ∈ ℕ, there are infinitely many square-free integers N, where the continued fraction expansion of has a fixed period. In this paper, we describe all polynomials for which the continued fraction expansion of has a fixed period. We also give a lower bound of the number of monic, non-squares polynomials Q such that deg Q = 2d and Per =t.

scholarly journals New Cryptanalytic Attack on RSA Modulus N=pq Using Small Prime Difference Method

Cryptography ◽  
2018 ◽  
Vol 3 (1) ◽  
pp. 2 ◽  
Author(s):  
Muhammad Ariffin ◽  
Saidu Abubakar ◽  
Faridah Yunos ◽  
Muhammad Asbullah
Keyword(s):  
Polynomial Time ◽  
Difference Method ◽  
Continued Fraction ◽  
Continued Fraction Expansion ◽  
Basis Reduction ◽  
Diophantine Approximations ◽  
Reduction Methods ◽  
Simultaneous Diophantine Approximations ◽  
Positive Integers ◽  
Better Than

This paper presents new short decryption exponent attacks on RSA, which successfully leads to the factorization of RSA modulus N = p q in polynomial time. The paper has two parts. In the first part, we report the usage of the small prime difference method of the form | b 2 p - a 2 q | < N γ where the ratio of q p is close to b 2 a 2 , which yields a bound d < 3 2 N 3 4 - γ from the convergents of the continued fraction expansion of e N - ⌈ a 2 + b 2 a b N ⌉ + 1 . The second part of the paper reports four cryptanalytic attacks on t instances of RSA moduli N s = p s q s for s = 1 , 2 , … , t where we use N - ⌈ a 2 + b 2 a b N ⌉ + 1 as an approximation of ϕ ( N ) satisfying generalized key equations of the shape e s d - k s ϕ ( N s ) = 1 , e s d s - k ϕ ( N s ) = 1 , e s d - k s ϕ ( N s ) = z s , and e s d s - k ϕ ( N s ) = z s for unknown positive integers d , k s , d s , k s , and z s , where we establish that t RSA moduli can be simultaneously factored in polynomial time using combinations of simultaneous Diophantine approximations and lattice basis reduction methods. In all the reported attacks, we have found an improved short secret exponent bound, which is considered to be better than some bounds as reported in the literature.

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