Comparison of various quantities as function of age among models with five different SFHs (standard, single local SFB, single global SFB, three local SFBs, and three global SFBs). Row 1: true SFR in different radial zones, divided into inner disc (R < 5 kpc, red), intermediate disc (5 < R < 11 kpc, blue) and outer disc (R > 11 kpc, green). The evolution at R_⊙ = 8 kpc is depicted by dashed blue curve. Row 2: SFH as observed today in the solar cylinder (7 < R < 9 kpc) after counting stellar radial migration. The vertical dotted line at 9 Gyr separates the disc (age >9 Gyr, red) from the disc (age <9 Gyr, blue). Row 3: evolution of [Fe/H] in the gas in different radial zones. Thick portions of curves indicate the periods of SFR higher than the time-averaged one. Row 4: [Fe/H] of stars existing in solar cylinder at the end of the simulation. The colour-coded filled contours represent the number density of stars. As shown on the left colour bar, the contour levels correspond to the fractions of 0.001, 0.1, 0.3, 0.5, 0.7, 0.9 of the total numbers of stars. The red and blue curves indicate the average [Fe/H] of the thin and thick discs. Row 5: evolution of [Si/Fe] in the gas in different radial zones. Row 6: [Si/Fe] in stars found in the solar cylinder at the end of the simulation. The fraction of young α-enhanced stars selected using the criterion from Chiappini et al. (2014) (magenta) and Zhang et al. (2021) (brown) are shown on the top left, along with the corresponding fractions of stars in those regions as obtained by our models (see text). Orange dots denote young, high [α/Fe] stars from Miglio et al. (2021).