{ "id": "2402.05230", "version": "v1", "published": "2024-02-07T20:09:59.000Z", "updated": "2024-02-07T20:09:59.000Z", "title": "Mittag-Leffler functions in the Fourier space", "authors": [ "Ahmed A. Abdelhakim" ], "categories": [ "math.CA", "math.AP" ], "abstract": "Let $\\alpha \\in (0,2)$ and let $\\beta>0$. Fix $-\\pi<\\varphi\\leq \\pi$ such that $|\\varphi|>\\alpha \\pi/2$. We determine the precise asymptotic behaviour of the Fourier transform of $E_{\\alpha,\\beta}(e^{\\dot{\\imath} \\varphi} |\\cdot|^{\\sigma})$ whenever $\\sigma>(n-1)/2$. Remarkably, this asymptotic behaviour turns out to be independent of $\\alpha$ and $\\beta$. This helps us determine the values of the Lebesgue exponent $p=p(\\sigma)$, $\\sigma>(n-1)/2$, for which $\\mathcal{F} \\left(E_{\\alpha,\\beta}(e^{\\dot{\\imath} \\varphi} |\\cdot|^{\\sigma})\\right)$ is in $L^{p}(\\mathbb{R}^{n})$. These values cannot be obtained via the Hausdorff-Young inequality. This problem arises in the study of space-time fractional equations. Our approach provides an effective alternative to the asymptotic analysis of the Fox $H-$ functions recently applied to the case $\\alpha \\in (0,1)$, $\\beta=\\alpha, 1$, $\\varphi=-\\pi/2,\\pi$. We rather rely on an appropriate integral representative that represents $E_{\\alpha,\\beta}$ continuously up to the origin, and we develop an extended asymptotic expansion for the Bessel function whose coefficients and remainder term are obtained explicitly.", "revisions": [ { "version": "v1", "updated": "2024-02-07T20:09:59.000Z" } ], "analyses": { "subjects": [ "30E15", "33E12", "42B10", "30E20", "34E05" ], "keywords": [ "mittag-leffler functions", "fourier space", "asymptotic behaviour turns", "precise asymptotic behaviour", "space-time fractional equations" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }