Well-poised generation of Ap\'ery-like recursions

The idea to use classical hypergeometric series and, in particular, well-poised hypergeometric series in diophantine problems of the values of the polylogarithms has led to several novelties in number theory and neighbouring areas of mathematics. Here we present a systematic approach to derive second-order polynomial recursions for approximations to some values of the Lerch zeta function, depending on the fixed (but not necessarily real) parameter $\alpha$ satisfying the condition $\Re(\alpha)<1$. Substituting $\alpha=0$ into the resulting recurrence equations produces the famous recursions for rational approximations to $\zeta(2)$, $\zeta(3)$ due to Ap\'ery, as well as the known recursion for rational approximations to $\zeta(4)$. Multiple integral representations for solutions of the constructed recurrences are also given.Comment: 8 pages; to appear in the Proceedings of the 7th OPSFA (Copenhagen, 18--22 August 2003

An Ap\'ery-like difference equation for Catalan's constant

Applying Zeilberger's algorithm of creative telescoping to a family of certain very-well-poised hypergeometric series involving linear forms in Catalan's constant with rational coefficients, we obtain a second-order difference equation for these forms and their coefficients. As a consequence we obtain a new way of fast calculation of Catalan's constant as well as a new continued-fraction expansion for it. Similar arguments can be put forward to indicate a second-order difference equation and a new continued fraction for $\zeta(4)=\pi^4/90$, and we announce corresponding results at the end of this paper.Comment: 10 pages; updating references (28 October 2002

Multiple qq-Zeta Values

We introduce a $q$-analog of the multiple harmonic series commonly referred to as multiple zeta values. The multiple $q$-zeta values satisfy a $q$-stuffle multiplication rule analogous to the stuffle multiplication rule arising from the series representation of ordinary multiple zeta values. Additionally, multiple $q$-zeta values can be viewed as special values of the multiple $q$-polylogarithm, which admits a multiple Jackson $q$-integral representation whose limiting case is the Drinfel'd simplex integral for the ordinary multiple polylogarithm when $q=1$. The multiple Jackson $q$-integral representation for multiple $q$-zeta values leads to a second multiplication rule satisfied by them, referred to as a $q$-shuffle. Despite this, it appears that many numerical relations satisfied by ordinary multiple zeta values have no interesting $q$-extension. For example, a suitable $q$-analog of Broadhurst's formula for $\zeta(\{3,1\}^n)$, if one exists, is likely to be rather complicated. Nevertheless, we show that a number of infinite classes of relations, including Hoffman's partition identities, Ohno's cyclic sum identities, Granville's sum formula, Euler's convolution formula, Ohno's generalized duality relation, and the derivation relations of Ihara and Kaneko extend to multiple $q$-zeta values.Comment: 35 page

Irrationality of values of zeta-function

We present several results on the number of irrational and linear independent values among $\zeta(s),\zeta(s+2),...,\zeta(s+2n)$, where $s>2$ is an odd integer and $n>0$ is an integer. The main tool in our proofs is a certain generalization of Rivoal's construction (math.NT/0008051, math.NT/0104221).Comment: 8+8 pages (English+Russian); to appear in the Proceedings of the Conference of Young Scientists (Moscow University, April 9-14, 2001