Integral means of derivatives of univalent functions in Hardy spaces

Fernando Pérez-González, Jouni Rättyä, Toni Vesikko

We show that the norm in the Hardy space $H^p$ satisfies \begin{equation}\label{absteq} \|f\|_{H^p}^p\asymp\int_0^1M_q^p(r,f')(1-r)^{p\left(1-\frac1q\right)}\,dr+|f(0)|^p\tag† \end…