On a family of differential-reflection operators: intertwining operators and Fourier transform of rapidly decreasing functions

Abstract: We introduce a family of differential-reflection operators $\Lambda_{A, \varepsilon}$ acting on smooth functions defined on $\mathbb R.$ Here $A$ is a Strum-Liouville function with additional hypotheses and $\varepsilon\in \mathbb R.$ For special pairs $(A,\varepsilon),$ we recover Dunkl's, Heckman's and Cherednik's operators (in one dimension). The spectral problem for the operators $\Lambda_{A, \varepsilon}$ is studied. In particular, we obtain suitable growth estimates for the eigenfunctions of $\Lambda_{A, \varepsilon}$. As the operators $\Lambda_{A, \varepsilon}$ are mixture of $d/dx$ and reflection operators, we prove the existence of an intertwining operator $V_{A,\varepsilon}$ between $\Lambda_{A, \varepsilon}$ and the usual derivative. The positivity of $V_{A,\varepsilon}$ is also established. Via the eigenfunctions of $\Lambda_{A,\varepsilon},$ we introduce a generalized Fourier transform $\mathcal F_{A,\varepsilon}.$ An $L^p$-harmonic analysis for $\mathcal F_{A,\varepsilon}$ is developed when $0<p\leq {2\over{1+\sqrt{1-\varepsilon^2}}}$ and $-1\leq \varepsilon\leq 1.$ In particular, an $L^p$-Schwartz space isomorphism theorem for $\mathcal F_{A,\varepsilon}$ is proved.