Typo in def 2.3.1

[tlacombe]

I don't know if this is the right place or use to do this, but I may have noticed a typo in the Definition 2.3.1 on p13. If my guess is correct, $\alpha_{i+1}$ should be replaced by $\alpha(t_{i+1})$.

[vkapovit]

Thank you! Yes, that was definitely a type. Fixed. If you see more please post here.