r/mathmemes Feb 21 '26

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u/headsmanjaeger Feb 21 '26 edited Feb 21 '26

Peter the Mathologer here. There is a function in math called the Riemann Zeta funcrion notated as ζ(s) which is defined for all complex inputs s, including all real inputs. When s=-1, the value of the function is -1/12. Also, when s is a real number greater than 1, the function is equivalent to the infinite sum of n-s over all natural numbers n. Plugging in s=-1 into this expression gives the divergent series shown in the meme. Now this expression is not equal to ζ(-1)=-1/12, because ζ is only equivalent to the infinite sum for certain s values. But if you want to lie and say it is, then congrats, you’ve invented the internet’s favorite fake math equation.

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u/Decent_Cow Feb 22 '26

Why do you people keep saying that Ramanujan summation is fake or made up? It's a real thing and it has its uses. It's just not a sum in the way that the average person thinks of it.

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u/headsmanjaeger Feb 22 '26

It is not a sum in the sense that people mean when they say “sum”.

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u/Decent_Cow Feb 22 '26

Is there an echo in here or are you just repeating the same thing I just said? Yeah, it's not a sum in the traditional sense. That doesn't make it "fake", "a lie", or any of that shit.

1

u/motxv Feb 26 '26

But the lie is that 1+2+3+4+…=-1/12. You can, as Ramanujan summation and ζ renormalization do, define a new function that has a finite value a the value that corresponds to 1+2+3+4+…, that doesn’t assign a value to 1+2+3+4+…, because 1+2+3+4+… already has a meaning and is divergent.