A Systematic Approach to Delay Functions

We present a systematic introduction to a class of functions that provide fundamental solutions for autonomous linear integer-order and fractional-order delay differential equations. These functions, referred to as delay functions, are defined through power series or fractional power series, with de...

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Main Authors: Christopher N. Angstmann, Stuart-James M. Burney, Bruce I. Henry, Byron A. Jacobs, Zhuang Xu
Format: Article
Language:English
Published: MDPI AG 2023-11-01
Series:Mathematics
Subjects:
Online Access:https://www.mdpi.com/2227-7390/11/21/4526
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author Christopher N. Angstmann
Stuart-James M. Burney
Bruce I. Henry
Byron A. Jacobs
Zhuang Xu
author_facet Christopher N. Angstmann
Stuart-James M. Burney
Bruce I. Henry
Byron A. Jacobs
Zhuang Xu
author_sort Christopher N. Angstmann
collection DOAJ
description We present a systematic introduction to a class of functions that provide fundamental solutions for autonomous linear integer-order and fractional-order delay differential equations. These functions, referred to as delay functions, are defined through power series or fractional power series, with delays incorporated into their series representations. Using this approach, we have defined delay exponential functions, delay trigonometric functions and delay fractional Mittag-Leffler functions, among others. We obtained Laplace transforms of the delay functions and demonstrated how they can be employed in finding solutions to delay differential equations. Our results, which extend and unify previous work, offer a consistent framework for defining and using delay functions.
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spelling doaj.art-59dee4d0a6c84986b9f0241fe30710d22023-11-10T15:08:10ZengMDPI AGMathematics2227-73902023-11-011121452610.3390/math11214526A Systematic Approach to Delay FunctionsChristopher N. Angstmann0Stuart-James M. Burney1Bruce I. Henry2Byron A. Jacobs3Zhuang Xu4School of Mathematics and Statistics, University of New South Wales, Sydney, NSW 2052, AustraliaSchool of Mathematics and Statistics, University of New South Wales, Sydney, NSW 2052, AustraliaSchool of Mathematics and Statistics, University of New South Wales, Sydney, NSW 2052, AustraliaDepartment of Mathematics and Applied Mathematics, University of Johannesburg, Johannesburg 2092, South AfricaSchool of Mathematics and Statistics, University of New South Wales, Sydney, NSW 2052, AustraliaWe present a systematic introduction to a class of functions that provide fundamental solutions for autonomous linear integer-order and fractional-order delay differential equations. These functions, referred to as delay functions, are defined through power series or fractional power series, with delays incorporated into their series representations. Using this approach, we have defined delay exponential functions, delay trigonometric functions and delay fractional Mittag-Leffler functions, among others. We obtained Laplace transforms of the delay functions and demonstrated how they can be employed in finding solutions to delay differential equations. Our results, which extend and unify previous work, offer a consistent framework for defining and using delay functions.https://www.mdpi.com/2227-7390/11/21/4526special functionsdelay differential equationsfractional differential equationsintegral transforms
spellingShingle Christopher N. Angstmann
Stuart-James M. Burney
Bruce I. Henry
Byron A. Jacobs
Zhuang Xu
A Systematic Approach to Delay Functions
Mathematics
special functions
delay differential equations
fractional differential equations
integral transforms
title A Systematic Approach to Delay Functions
title_full A Systematic Approach to Delay Functions
title_fullStr A Systematic Approach to Delay Functions
title_full_unstemmed A Systematic Approach to Delay Functions
title_short A Systematic Approach to Delay Functions
title_sort systematic approach to delay functions
topic special functions
delay differential equations
fractional differential equations
integral transforms
url https://www.mdpi.com/2227-7390/11/21/4526
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