grandes-ecoles 2022 Q4

grandes-ecoles · France · x-ens-maths-c__mp Sequences and Series Properties and Manipulation of Power Series or Formal Series

Show that $\widehat{f \cdot g} \prec \hat{f} \cdot \hat{g}$, deduce that $\rho(f \cdot g) \geqslant \min(\rho(f), \rho(g))$.

Show that $\widehat{f \cdot g} \prec \hat{f} \cdot \hat{g}$, deduce that $\rho(f \cdot g) \geqslant \min(\rho(f), \rho(g))$.