Definitions of Fractional derivative

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Discussion Overview

The discussion revolves around the various definitions of fractional derivatives, specifically questioning the equivalence of these definitions, including the Riemann-Liouville differintegral, Grunwald-Letnikov derivative, Hadamard, and Caputo derivatives. The scope includes theoretical aspects of fractional calculus.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant asks about the number of definitions for fractional derivatives beyond the Riemann-Liouville differintegral and whether they are all equivalent.
  • Another participant mentions the Grunwald-Letnikov derivative and asserts that all definitions are equivalent, suggesting that having multiple definitions for the same concept is pointless.
  • A different viewpoint argues that having multiple definitions is not pointless but indicates inconsistency among them.
  • One participant introduces the Hadamard and Caputo derivatives and requests links to their definitions, expressing a concern about the complexity of the Riemann-Liouville differintegral when calculating integer derivatives.

Areas of Agreement / Disagreement

Participants express disagreement regarding the equivalence of the various definitions of fractional derivatives, with some asserting equivalence while others highlight inconsistencies.

Contextual Notes

There are unresolved questions regarding the assumptions underlying the definitions and their applicability, as well as the implications of using different definitions in practice.

Klaus_Hoffmann
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how many definitions appart from the 'Riemann-Liouville differintegral' to define the fractional derivative of f(x) or [tex]x^{a}f(x)[/tex] for real or complex 'a' are them all equivalents??
 
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The other variation is the Grunwald-Letnikov Derivative, and all definitions are equivalent. It's pretty pointless if you have 2 different definitions for the same thing..
 
not pointless, but inconsistent.
 
I heard also about Hadamard and Caputo derivatives for fractional calculus could anyone give a link with the definition?

a great inconvenient i see to Riemann-Liouville differintegral is the fact that for an integer m you must calculate expression [tex]\frac{d^{m}}{dx^{m}}[/tex]
 

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