scholarly journals Diophantine Approximations of Infinite Series and Products

2016 ◽  
Vol 24 (1) ◽  
pp. 71-82 ◽  
Author(s):  
Ondřej Kolouch ◽  
Lukáš Novotný

Abstract This survey paper presents some old and new results in Diophantine approximations. Some of these results improve Erdos’ results on irrationality. The results in irrationality, transcendence and linear independence of infinite series and infinite products are put together with idea of irrational sequences and expressible sets.

Author(s):  
Tapani Matala-aho

Given a sequence of linear forms in m ≥ 2 complex or p-adic numbers α1, …,αm ∈ Kv with appropriate growth conditions, Nesterenko proved a lower bound for the dimension d of the vector space Kα1 + ··· + Kαm over K, when K = Q and v is the infinite place. We shall generalize Nesterenko's dimension estimate over number fields K with appropriate places v, if the lower bound condition for |Rn| is replaced by the determinant condition. For the q-series approximations also a linear independence measure is given for the d linearly independent numbers. As an application we prove that the initial values F(t), F(qt), …, F(qm−1t) of the linear homogeneous q-functional equation where N = N(q, t), Pi = Pi(q, t) ∈ K[q, t] (i = 1, …, m), generate a vector space of dimension d ≥ 2 over K under some conditions for the coefficient polynomials, the solution F(t) and t, q ∈ K*.


2015 ◽  
Vol 23 (2) ◽  
pp. 107-120
Author(s):  
Jaroslav Hančl ◽  
Ondřej Kolouch ◽  
Lukáš Novotný

Abstract Using an idea of Erdős the paper establishes a criterion for the linear independence of infinite products which consist of rational numbers. A criterion for irrationality is obtained as a consequence.


2008 ◽  
Vol 51 (1) ◽  
pp. 32-46 ◽  
Author(s):  
Stephen Choi ◽  
Ping Zhou

AbstractLet q,m,M ≥ 2 be positive integers and r1, r2, … , rm be positive rationals and consider the following M multivariate infinite productsfor i = 0, 1, … ,M –1. In this article, we study the linear independence of these infinite products. In particular, we obtain a lower bound for the dimension of the vector space ℚF0+ℚF1+· · ·+ℚFM–1+ℚ over ℚ and show that among these M infinite products, F0, F1, … , FM–1, at least ∼ M/m(m + 1) of them are irrational for fixed m and M → ∞.


2019 ◽  
Vol 31 (6) ◽  
pp. 1557-1566
Author(s):  
Daniel Duverney ◽  
Yohei Tachiya

AbstractIn this paper, we refine the method of Chowla and Erdős on the irrationality of Lambert series and study a necessary condition for the infinite series {\sum\theta(n)/q^{n}} to be a rational number, where q is an integer with {|q|>1} and θ is an arithmetic function with suitable divisibility and growth conditions. As applications of our main theorem, we give linear independence results for various kinds of Lambert series.


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