Single-valuedness of the AdS Veneziano amplitude

We consider the Veneziano amplitude for the scattering of gluons in type IIB string theory on $Ad{S}_5\times S^5\mathrm{/}{\mathbb{Z}}_2$ in the presence of D7 branes. On general grounds curvature corrections around flat space can be thought of as arising from the extra insertion of soft gravitons. This naturally leads to an open string world-sheet representation with the extra insertion of single-valued functions evaluated on the real line. We check that the recently obtained first curvature correction is of this form and use this new constraint to compute the second curvature correction of the AdS Veneziano amplitude.