Multiple zeta values and multiple Ap\'ery-like sums

Abstract

In this paper, we formally introduce the notion of Ap{\'e}ry-like sums and we show that every multiple zeta values can be expressed as a $\bf Z$-linear combination of them. We even describe a canonical way to do so. This allows us to put in a new theoretical context several identities scattered in the literature, as well as to discover many new interesting ones. We give in this paper new integral formulas for multiple zeta values and Ap\'ery-like sums. They enable us to give a short direct proof of Zagier's formulas for $\zeta(2,\ldots,2,3,2,\ldots,2)$ as well as of similar ones in the context of Ap{\'e}ry-like sums. The relations between Ap\'ery-like sums themselves still remain rather mysterious, but we get significant results and state some conjectures about their pattern.