Decay estimates for a class of Dunkl wave equations

Abstract: Let $\Delta_\kappa$ be the Dunkl Laplacian on $\mathbb{R}^n$ and $\phi: \mathbb{R}^+ \to \mathbb{R}$ is a smooth function. The aim of this manuscript is twofold. First, we study the decay estimate for a class of dispersive semigroup of the form $e^{it\phi(\sqrt{-\Delta_\kappa})}$.W e overcome the difficulty arising from the non-homogeneousity of $\phi$ by frequency localization. As applications, in the next part of the paper, we establish Strichartz estimates for some concrete wave equations associated with the Dunkl Laplacian $\Delta_k,$ which corresponds to $\phi(r)=r, r^2, r^2+r^4, \sqrt{1+r^2}, \sqrt{1+r^4}$, and $r^\mu,0<\mu\leq 2, \mu\neq 1$. More precisely, we unify and simplify all the known dispersive estimates and extend to more general cases. Finally, using the decay estimates, we prove the global-in-time existence of small data Sobolev solutions for the nonlinear Klein-Gordon equation and beam equation with the power type nonlinearities.