An Integral Expression for the Dunkl Kernel in the Dihedral Setting
In this paper, we establish an integral expression for the Dunkl kernel in the context of Dihedral group of an arbitrary order by using the results in \cite{M-Y-Vk} where a construction of the Dunkl intertwining operator for a large set of regular parameter functions is provided. We introduce a differential equations systems that leads to the explicit expression of the Dunkl Kernel whenever an appropriate solution of it is obtained. In particular, an explicit expression of the Dunkl kernel $E_k(x,y)$ is given when one of its argument $x$ or $y$ is invariant under the action of a known reflection in the dihedral group. We obtain also a generating series for the homogeneous components $E_m(x,y)$, $m\in\mathbb{Z}^{+}$, of the Dunkl kernel from which we derive new sharp estimates for the Dunkl kernel when the parameter function $k$ satisfies $\mathrm{Re}(k)>-\nu$, $\nu$ an arbitrary nonnegative integer, which, up to our knowledge, is the largest context for such estimates so far.