Keijo Väänänen
University of Oulu
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Publication
Featured researches published by Keijo Väänänen.
Bulletin of The Australian Mathematical Society | 1994
Ari Heimonen; Tapani Matala-aho; Keijo Väänänen
The paper provides irrationality measures for certain values of binomial functions and definite integrals of some rational functions. The results are obtained using Jacobi type polynomials and divisibility considerations of their coefficients.
Results in Mathematics | 2005
Peter Bundschuh; Keijo Väänänen
Let K be ℚ or an imaginary quadratic number field, and q ∈ K an integer with ¦q¦ > 1. We give a quantitative version of Σn≥1 an/(qn − 1) ∉ K for non-zero periodic sequences (an) in K of period length ≤ 2. As a corollary, we get a quantitative version of the linear independence over K of 1, the q-harmonic series, and a q-analogue of log 2. A similar result on 1, the q-harmonic series, and a q-analogue of ζ(2) is also proved. Mathematics Subject Classification (2000): 11J72, 11J82
Mathematics of Computation | 2005
Tapani Matala-aho; Keijo Väänänen; Wadim Zudilin
The three main methods used in diophantine analysis of q-series are combined to obtain new upper bounds for irrationality measures of the values of the q-logarithm function when p = 1/q ∈ Z \ {0, ±1} and z ∈ Q.
Manuscripta Mathematica | 1993
Ari Heimonen; Tapani Matala-aho; Keijo Väänänen
The paper gives irrationality measures for the values of some Gauss hypergeometric functions both in the archimedean andp-adic case. Further, an improvement of general results is obtained in the case of logarithmic function.
IEEE Transactions on Information Theory | 1999
Marko J. Moisio; Keijo Väänänen
Two recursive algorithms for computing the weight distributions of certain binary irreducible cyclic codes of length n in the so-called index 2 case are presented. The running times of these algorithms are smaller than O(log/sup 2/r) where r=2/sup m/ and n is a factor of r-1.
Canadian Mathematical Bulletin | 2005
Keijo Väänänen; Wadim Zudilin
We obtain lower estimates for the absolute values of linear forms of the values of generalized Heine series at non-zero points of an imaginary quadratic field II, in particular of the values of q-exponential function. These estimates depend on the individual coefficients, not only on the maximum of their absolute values. The proof uses a variant of classical Siegels method applied to a system of functional Poincare-type equations and the connection between the solutions of these functional equations and the generalized Heine series.
Manuscripta Mathematica | 1989
Keijo Väänänen; R. Wallisser
We consider arithmetic properties of the solution of a functional equation f(qx)=xf(x)+1, where q≠0 is a rational number satisfying certain conditions. A linear independence measure is obtained for the values of f and its derivatives at rational points, both in the archimedian and p-adic case. The proof uses a refinement of the method followed by skolem in the corresponding qualitative considerations.
International Journal of Number Theory | 2015
Keijo Väänänen
We shall obtain the irrationality exponent 2 for some values of two special Mahler functions. This gives a new proof for the recent result of Bugeaud on Thue–Morse–Mahler numbers.
Acta Arithmetica | 2009
Christian Krattenthaler; Igor Rochev; Keijo Väänänen; Wadim Zudilin
We investigate arithmetic properties of values of the entire function
Journal of The Australian Mathematical Society | 2015
Peter Bundschuh; Keijo Väänänen