Resummation of divergent integrals.

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Discussion Overview

The discussion revolves around the resummation of divergent integrals, particularly in the context of mathematical methods and their applicability to integrals similar to those used in quantum field theory (QFT). Participants explore the potential for developing techniques analogous to those used for divergent series.

Discussion Character

  • Exploratory, Debate/contested, Technical explanation

Main Points Raised

  • One participant questions the absence of resummation methods for divergent integrals, citing examples such as \(\int_{0}^{\infty} dx x^{s-1}\) and \(\int_{0}^{\infty} dx (x+1)^{-1} (x^{3}+x)\).
  • Another participant references the Ramanujan sum, suggesting it as a potential method, but emphasizes the need for a similar approach applicable to integrals.
  • There is a challenge posed regarding the necessity of developing such methods, with a participant questioning the rationale behind needing resummation techniques for integrals.
  • A later reply mentions that in quantum field theory, many integrals diverge, such as \(\int_{0}^{\infty} dk k^{n}\), proposing this as a valid reason to seek resummed values for integrals.

Areas of Agreement / Disagreement

Participants express differing views on the necessity and feasibility of resummation methods for divergent integrals. There is no consensus on whether such methods should exist or how they might be developed.

Contextual Notes

Participants reference specific divergent integrals and series, but the discussion remains open-ended regarding the methods and their applicability. The mathematical steps and assumptions underlying the proposed ideas are not fully explored.

mhill
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if we can obtain resummation methods for divergent series such as

[tex]1-1+1-1+1-1+1-1+...[/tex] or [tex]1!-2!+3!-4!+..[/tex]

my question is why is there no method to deal with divergent integrals like [tex]\int_{0}^{\infty} dx x^{s-1}[/tex] or [tex]\int_{0}^{\infty} dx (x+1)^{-1} (x^{3}+x)[/tex]
 
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Do you mean the ramanujan sum?
 
*-<|:-D=<-< said:
Do you mean the ramanjuan sum?


yes something similar but for integrals instead of being valid only for series .
 
mhill said:
my question is why is there no method to deal with divergent integrals


My question is: why should there be? If you can think of a good reason, then perhaps you will find a way to do it. (Is this you again, eljose?)
 
Can you recall any method of writing an integral as a sum?
 
matt grime said:
My question is: why should there be? If you can think of a good reason, then perhaps you will find a way to do it. (Is this you again, eljose?)

the question is that for example in QFT many integrals diverge as [tex]\int_{0}^{\infty} dk k^{n}[/tex] that would be a good reason to try finding resummed values of integrals.
 

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