Continuation of Radial Positive Definite Functions and Their Characterization

This paper delves into the extension and characterization of radial positive definite functions into non-integer dimensions. We provide a thorough investigation by employing the Riemann–Liouville fractional integral and fractional Caputo derivatives, enabling a comprehensive understanding of these f...

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Main Author: Fethi Bouzeffour
Format: Article
Language:English
Published: MDPI AG 2023-08-01
Series:Fractal and Fractional
Subjects:
Online Access:https://www.mdpi.com/2504-3110/7/8/623
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author Fethi Bouzeffour
author_facet Fethi Bouzeffour
author_sort Fethi Bouzeffour
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description This paper delves into the extension and characterization of radial positive definite functions into non-integer dimensions. We provide a thorough investigation by employing the Riemann–Liouville fractional integral and fractional Caputo derivatives, enabling a comprehensive understanding of these functions. Additionally, we introduce a secondary characterization based on the Bernstein characterization of completely monotone functions. The practical significance of our study is showcased through an examination of the positivity of the fundamental solution of the space-fractional Bessel diffusion equation, highlighting the real-world applicability of the developed concepts. Through this work, we contribute to the broader understanding of radial positive definite functions and their utility in diverse mathematical and applied contexts.
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spelling doaj.art-9b0b5ccf1ed14ed1bab5e152a0c6075c2023-11-19T01:11:45ZengMDPI AGFractal and Fractional2504-31102023-08-017862310.3390/fractalfract7080623Continuation of Radial Positive Definite Functions and Their CharacterizationFethi Bouzeffour0Department of Mathematics, College of Sciences, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi ArabiaThis paper delves into the extension and characterization of radial positive definite functions into non-integer dimensions. We provide a thorough investigation by employing the Riemann–Liouville fractional integral and fractional Caputo derivatives, enabling a comprehensive understanding of these functions. Additionally, we introduce a secondary characterization based on the Bernstein characterization of completely monotone functions. The practical significance of our study is showcased through an examination of the positivity of the fundamental solution of the space-fractional Bessel diffusion equation, highlighting the real-world applicability of the developed concepts. Through this work, we contribute to the broader understanding of radial positive definite functions and their utility in diverse mathematical and applied contexts.https://www.mdpi.com/2504-3110/7/8/623positive definite functionscompletely monotone functionsfractional integral and derivativefractional diffusion equation
spellingShingle Fethi Bouzeffour
Continuation of Radial Positive Definite Functions and Their Characterization
Fractal and Fractional
positive definite functions
completely monotone functions
fractional integral and derivative
fractional diffusion equation
title Continuation of Radial Positive Definite Functions and Their Characterization
title_full Continuation of Radial Positive Definite Functions and Their Characterization
title_fullStr Continuation of Radial Positive Definite Functions and Their Characterization
title_full_unstemmed Continuation of Radial Positive Definite Functions and Their Characterization
title_short Continuation of Radial Positive Definite Functions and Their Characterization
title_sort continuation of radial positive definite functions and their characterization
topic positive definite functions
completely monotone functions
fractional integral and derivative
fractional diffusion equation
url https://www.mdpi.com/2504-3110/7/8/623
work_keys_str_mv AT fethibouzeffour continuationofradialpositivedefinitefunctionsandtheircharacterization