Wait....the debate is finally settled...
In fact in week 41 Genoa will play against Mantova so neither of them will get out with full points.
If Genoa win/draw , Mantova will be 10+ points behind the 3rd team on the table, so no play-off is required.
If Mantova win/draw, Genoa will have less points than Juve and Juve will get promoted.
So it's true that Juve will be mathematically promoted if the beat Arezzo