Panel a: selected inner disk stars from the sample of Adibekyan et al. (2012), together with our models (blue curves). The stars are selected above the fiducial model lowered down in [α/Fe] by 0.025 dex (black curve) in the [Fe/H]-[α/Fe] distribution. The color scale codes the age of the stars from Haywood et al. (2013). Panel b: age-metallicity distribution of inner-disk stars described in the text. The observed distribution widens at younger age (< 5 Gyr) because of the increasing difficulty in separating the inner disk sequence from the OLR (local) stars at lower alphas. Panel c: age-[α/Fe] relation for the selected stars, together with the model. The three points with larger symbols are apparently young, alpha-rich objects. The black triangles indicate the position of NGC 6791 at age = 6.8 Gyr, [Fe/H] = +0.3 and [α/Fe] = +0.036 (see text for references).