Is there someone who knows the following paper

"Local well-posedness for the Maxwell-Schrodinger system" by M.Nakamura and T.Wada.

I'm trying to study it but I've some doubts. In particular I'm not really understanding where the use the assumption $s\geq \frac{5}{3}$

Is there someone who knows the following paper

"Local well-posedness for the Maxwell-Schrodinger system" by M.Nakamura and T.Wada.

I'm trying to study it but I've some doubts. In particular I'm not really understanding where they use the assumption $s\geq \frac{5}{3}$.