Spectra of integration operators and weighted square functions Alexandru AlemanJose Pelaez 30H1047A1026D10Hardy spacessquare functions$\mathcal{A}_{\infty}$-weightsintegration operatorsspectra Motivated by the study of the spectrum of integration operators \[ T_gf(z) = \int_0^zf(\xi)g'(\xi)\mathrm{d}\xi, \] acting on the Hardy spaces $H^p$, we prove weighted versions of the classical estimates due to Fefferman-Stein and Littlewood-Paley which express the $H^p$-norm of an analytic function with help of its derivative. Indiana University Mathematics Journal 2012 text pdf 10.1512/iumj.2012.61.4647 10.1512/iumj.2012.61.4647 en Indiana Univ. Math. J. 61 (2012) 775 - 793 state-of-the-art mathematics http://iumj.org/access/