Left: effect of the initial stellar mass M and of an exponentially decaying core-boundary mixing profile with parameter f_ov on evolutionary tracks. Mass (M = 10 (black), 12 (red), and 15 M_⊙ (blue)) and mixing (f_ov = 0.005 (solid), 0.020 (dashed), and 0.040 H_p (dotted)) sequences are shown with color and line style, respectively. Solar metallicity Z = 0.014 is assumed. Right: effect of the initial stellar mass M and the metallicity Z on evolutionary tracks. The mass sequence is the same as in the left panel; line styles show the metallicity sequence Z = 0.010 (dashed), 0.014 (solid), and 0.018 (dotted) in mass fraction units. A fixed parameter f_ov = 0.005 H_p is assumed. Note the difference in X, Y-axes in the two panels.