On q-summation and confluence

This paper is divided in two parts. In the first part we consider a convergent q-analog of the divergent Euler series, with q ∈ (0, 1), and we show how the Borel sum of a generic Gevrey formal solution to a differential equation can be uniformly approximated on a convenient sector by a meromorphic solution of a corresponding q-difference equation. In the second part, we work under the assumption q ∈ (1,+∞). In this case, at least four different q-Borel sums of a divergent power series solution of an irregular singular analytic q-difference equations are spread in the literature: under convenient assumptions we clarify the relations among them.