Posts: 1,399
Threads: 342
Joined: Feb 2009
Does the Mellin transform have a half-iterate ?
After all these half-iterates of functions , integrals and derivatives, I wonder ( again ) about half-iterates of integral transforms.
regards
tommy1729
Posts: 341
Threads: 73
Joined: Dec 2010
Well I posted a reply to this but it deleted it :/
I have looked at this for so long Tommy. It's very closely related to tetration. I'll tell you how I can do it for some functions.
define
Then if
then
However we have to show lots of conditions on convergence and what not.
Posts: 1,399
Threads: 342
Joined: Feb 2009
I notice that Im not so comfortable with many iteration of the Mellin transform.
Convergeance issues seem to pop up out of nowhere.
For instance if we start with f(x) = exp(x) or f(x) = exp(-x) we get in trouble before we reach the 3rd iteration of the mellin transform.
And if we pick an elementary function between exp(x) and exp(-x), I seem to have trouble finding a closed form for every n th mellin transform.
Maybe I need to consider using hypergeometrics ?
What are standard tables of n th mellin transforms (for s,x > 0) , if that has even been made yet ?
regards
tommy1729
Posts: 1,399
Threads: 342
Joined: Feb 2009
Also of intrest to me are integral transforms that are cyclic :
Like for almost all f,s and some transform M :
M^[3](f)(s) = f(s) but M^[1](f)(s) =/= f(s) and M^[2](f)(s) =/= f(s).
I assume this is consistant with Schwartz kernel theorem.
As Kernel I assume abelian functions could be used. And maybe some others too ?
regards
tommy1729
Posts: 1,399
Threads: 342
Joined: Feb 2009
Ok this has given me an idea for tetration ...
The James-tommy method is in progress
regards
tommy1729