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Aug 9 at 6:42 comment added Dr Potato This is the most super-duplicate question I've seen in this forum so far, and there are good reasons why nobody mark them all as the same. This is because yet we want to see things from several angles. If it indeed may be solved with Fourier analysis, it could be done the other way around. I could say: Fourier is in time (additive) shifts and Mellin in scale shifts (multiplicative) And still I ask: So what is the Inverse Mellin transform anyways?
S Apr 21, 2018 at 22:34 history suggested kjetil b halvorsen CC BY-SA 3.0
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Apr 13, 2017 at 12:58 history edited CommunityBot
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Feb 19, 2013 at 17:11 answer added Michael Rubinstein timeline score: 9
Feb 13, 2012 at 12:21 answer added user19475 timeline score: 4
Nov 13, 2011 at 4:25 answer added Phil Isett timeline score: 18
Nov 13, 2011 at 1:07 answer added Frank Thorne timeline score: 24
Nov 4, 2011 at 0:40 answer added paul garrett timeline score: 29
Nov 3, 2011 at 20:33 history edited mathphysicist
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Nov 3, 2011 at 14:52 history edited Frank Thorne CC BY-SA 3.0
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Nov 3, 2011 at 13:38 answer added Tom Copeland timeline score: 12
Nov 3, 2011 at 1:33 comment added Matt Young I think of the Mellin transform as the equivalent gadget to the Fourier transform, but for the group of positive reals instead of the real line. The change of variables going from one transform to the other is either an exponential or log (depending on which way it's going) which corresponds to the usual isomorphism between the two groups. The function $t \rightarrow t^s$ is a character on the positive reals which is analogous to the function $x \rightarrow e^{2 \pi i x y}$ which is a character on the real line. The Mellin transform is natural for studying multiplicative functions.
Nov 3, 2011 at 0:50 comment added Peter Humphries I agree with Greg here that Montgomery and Vaughan is a good pointer on why Mellin inversion works. But personally, the only justification I need is changing variables so that it becomes the same as Laplace inversion. This change of variables shows why one integral is over the positive reals while the other is a line integral in the complex plane. Of course, this all depends on how willing you are to believe why Laplace inversion is morally true, or Fourier inversion, for that matter.
Nov 3, 2011 at 0:06 comment added Aaron Bergman Shouldn't this be something like Pontryagin duality for the multiplicative group of positive reals (maybe with some analytic continuation thrown in?).
Nov 2, 2011 at 23:44 comment added Gerry Myerson Morally, why is the Fourier inversion formula true? Morally, why is the Laplace inversion formula true?
Nov 2, 2011 at 23:15 comment added Greg Martin You could also take a look at section 5.1 of Montgomery and Vaughan's Multiplicative Number Theory. It has several specific examples of Mellin transform pairs, together with brief remarks on how the formulas are proved. I believe that the basic method really is the same as Perron's formula: if $y$ is small then you drag the contour integral to the right and get a contribution of $0$, while if $y$ is large then you drag the contour to the left and pick up the residue of the integrand at $s=0$.
Nov 2, 2011 at 21:55 history asked Frank Thorne CC BY-SA 3.0