Current SFR as a function of stellar mass of the z ~ 4 LBGs obtained for different SF histories. Same symbols as Fig. 4. The dotted and dash-dotted lines delimit the area above which galaxies with L_IR ≳ 2. × 10¹¹ L_⊙ (or equivalently a flux  >0.2 mJy in ALMA band 7 (approximately at band center,  ~950 μm) for T_d = 35 K) or  >2. × 10¹⁰ L_⊙, respectively, are found. The dashed line shows the SFR-mass relation at z ~ 2 for comparison.