Mixed norm estimates for the Cesàro means associated with Dunkl--Hermite expansions

Abstract: Our main goal in this article is to study mixed norm estimates for the Ces`{a}ro means associated with Dunkl--Hermite expansions on $\mathbb{R}^d$. These expansions arise when one consider the Dunkl--Hermite operator (or Dunkl harmonic oscillator) $H_{\kappa}:=-\Delta_{\kappa}+|x|^2$, where $\Delta_{\kappa}$ stands for the Dunkl--Laplacian. It is shown that the desired mixed norm estimates are equivalent to vector-valued inequalities for a sequence of Ces`{a}ro means for Laguerre expansions with shifted parameter. In order to obtain the latter, we develop an argument to extend these operators for complex values of the parameters involved and apply a version of three lines lemma.