Can someone me check something.

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Discussion Overview

The discussion revolves around a potential error in the presentation of the Riemann Zeta Function on a webpage from MathWorld. Participants are examining whether the restriction of the variable "x" to integer values in certain equations is justified or if it is an oversight.

Discussion Character

  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant questions the necessity of restricting "x" to integer values in the equations presented on the MathWorld page, suggesting that the integral is valid for all "x".
  • Another participant agrees that the integral is valid for real "x" (specifically for "x > 1") but expresses confusion over why the summation is limited to integer values.
  • A later reply supports the initial concern, stating that the restriction to natural values of "x" does not impact the calculations involved.
  • One participant acknowledges the correctness of the initial claim about the restriction being unnecessary.
  • There is a clarification regarding the name of a participant, indicating a mix-up in attribution.

Areas of Agreement / Disagreement

Participants generally agree that the restriction of "x" to integer values is not necessary for the calculations discussed, although some initial confusion existed regarding the summation and its variables.

Contextual Notes

There is an emphasis on the distinction between the integral's validity for all "x" and the specific context of the infinite sum, which may have led to the misunderstanding regarding the restriction to integers.

uart
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Hi, I was reading a derivation over at mathworld.wolfram and I struck something that looks simple enough but I can't quite see it. I think it might be a mistake in the web-page but I'd just like to get second (or 3rd 4th etc) opinion on it.

The page in question is here : http://mathworld.wolfram.com/RiemannZetaFunction.html"

I know there's some heavy stuff on that page but trust me that my issue is a fairly simple one. If you scroll down past the preamble and graphs until you come to the numbered equations, the part I have an issue with is in equations 1 through to 7.

Specifically the part where it says "If x is an integer n, then we have the identity" (just after numbered equation 1). In that section from equation 1 through 7 I just can't see anything at all that would require x be restricted to integers. Is it just me or do you think that the page is in error when it suggests that x needs to be an integer here?

Thanks in advance.
 
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The integral is valid for all values of "x", the discussion of the infinite sum is specialized for "x" integer, and an integer is commonly denoted by "n".

So i don't see your problem.
 
dextercioby said:
The integral is valid for all values of "x", the discussion of the infinite sum is specialized for "x" integer, and an integer is commonly denoted by "n".

So i don't see your problem.

Yes I know that the integral is valid for real x (actually x>1), but I don't see why the sum is restricted to integer values of the argument.

Please read it carefully and note that the summation dummy variable (k in that text) has absolutely nothing to do with whether or not the argument of the function (x or n in that text) is integer or otherwise.
 
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On a better reading, you're right, it makes no sense to restrict the discussion to natural values of "x", as it doesn't affect the calculation.
 
That's what I thought. Thanks for verifying it Kurt.
 
His name is Daniel, by the way, not Kurt
 
arildno said:
His name is Daniel, by the way, not Kurt

Doh I see it now, Kurt Lewin is the author of one of the quotes in his sig. Blush :blushing:
 
Last edited:

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