Talk:Summation

Sum of 1, off by 1?

This seems like a trivial thing, but seems to be incorrect in the listing.

The sum of 1 from m to n is n - m + 1, not n - m. A trivial example, sum 1 from 1 to 10, the answer is not (10 - 1 = 9), it is (10 - 1 + 1 = 10). — Preceding unsigned comment added by 68.13.40.239 (talk) 04:46, 10 September 2011 (UTC)

Right; this is corrected now. As a general rule summation expressions would be simpler if the upper limit in a summation would have been the first value not to include rather than the last value to include, but it's too late to change that convention. Note that n + 1 occurs more frequently in the expressions of the section in question than n (and this is why I wrote n + 1 − m rather than n − m + 1). Marc van Leeuwen (talk) 08:44, 10 September 2011 (UTC)

I disagree with that "should have been". Your perspective is one derived from programmers (is it not?) who initiated their own convention long after mathematics had theirs. Youre assuming one is wrong because youve accepted the other. It's a perfect example of bias. Am I wrong? Can you justify precisely why the convention *should* have been different without presupposing the other? NicholasSweeten (talk) 23:46, 23 July 2018 (UTC)

Less than 2 terms?!

Hello to Wikipedia Community,

This is my first ever Wikipedia talk post. Please excuse my stupidity!

I am a dumb, ignorant, old guy going back to school to learn math. So, I read this article and find the statement "It is possible to sum fewer than 2 numbers". Really? That seems, to me, anyway, to violate the logic of a definition of a sum; a sum means we are adding one value to another value (or more values). Why would we even bother to try to denote this impossible concept of a sum of one or zero values? That just does not make sense to me. Wouldn't we just instead say that the starting conditions "m = n" or "m > n" are just not allowed or undefined, in the same manner as we might say "any value divided by zero is undefined"? Please explain.

Cheers, Allan — Preceding unsigned comment added by Allan.w.macdonald (talk • contribs) 02:12, 7 September 2012 (UTC)

You deal with sums of a single number all the time. Every time you go to a store and buy a single item, there's a line on the receipt that says "total" (er, well, "subtotal") with just the price of that one item, right? So the sum of a single item is really not an impossible concept—it's a very useful concept, in fact. —Bkell (talk) 03:01, 7 September 2012 (UTC)

A sum of zero numbers is similar. Imagine that you have a bank account into which you make no deposits for a certain month. At the end of the month you will get a statement from the bank with a line that says something like, "Total deposits $0.00." That's a sum of no numbers! —Bkell (talk) 03:04, 7 September 2012 (UTC)

Its probably best not to think of it as literal adding. Rather, think of it is a convention. Something formal mathematics has been forced to accept for consistency. Its not without its logic. NicholasSweeten (talk) 23:48, 23 July 2018 (UTC)

Content dispute

@172.77.243.224: Can you please explain why you removed a bunch of information? @Citizen Canine: and @Gdog1102:, what do you think about this? INeedSupport^{(Care free to give me support?)} 01:34, 25 October 2018 (UTC)

Nevermind. It would appear that the IP was vandalizing the article INeedSupport^{(Care free to give me support?)} 02:08, 25 October 2018 (UTC)

184.13.109.29 (talk) 18:05, 25 October 2018 (UTC) D Lazard edited the page again. Here is how I can tell: The banner at the top of the page https://wiki.riteme.site/wiki/Summation reads "This article may require cleanup to meet Wikipedia's quality standards." When I edit the page, the banner goes away. I tried editing the summation page to fit the wiki encyclopedia style. I also revised the grammar, spelling, and references for correctness and clarity. D Lazard likes his(her) version. The first sentence has a personal pronoun referring to a sum. Keep reading each sentence...more errors follow. 184.13.109.29 (talk) 18:05, 25 October 2018 (UTC)

184.13.109.29 (talk) 18:54, 25 October 2018 (UTC) Here are some more edits: 1) The "Formal Definitions" section does not define recursion. 2) The last formula in the section titled "Summation index in exponents" is a partial proof. Remove the derivation. 3) The section titled "Growth rates" is irrelevant to this page. Delete the entire section and add it to a different wiki page. 4) The section titled "Miscellaneous" has an existing wiki page on harmonic numbers. Delete this section and add it to the wiki page on harmonic numbers. 5) The links for the citation to Graham et. al. either do not work or are irrelevant to the citation. Remove the links.

Most likely, there are other errors on this page. 184.13.109.29 (talk) 18:54, 25 October 2018 (UTC)

I'll look at the information to see if you're correct, should I have time to do that. INeedSupport^{(Care free to give me support?)} 23:15, 25 October 2018 (UTC)

@184.13.109.29: Update: Looks like RLGoodwin is doing the work there. INeedSupport^{(Care free to give me support?)} 23:17, 25 October 2018 (UTC)

Incorrect General Identities

I KEEP removing these identities and someone keeps putting them right back in without checking correctness. Distributivity and factorization on the list are INVALID. If it doesnt work for a binomial why would anyone assume it worked for an arbitrary series? Hate fighting idiots on wikipedia. If you are weak at math and dont know what youre talking about, and wont even research, then quit contributing. Simple. Im starting to think its malice rather than stupidity. 50.125.86.70 (talk) 18:41, 25 February 2019 (UTC)

Which identities are wrong and what are the correct identities? Note that in the comments, "distributivity", ... do not mean that the identity makes the property explicit, but rather that this is used for proving the identity. D.Lazard (talk) 19:20, 25 February 2019 (UTC)

I hope you don't refer to the identity like (A, B, C are integers for the moment)

$A^{n}=\sum _{X=1}^{A}(X^{n}-(X-1)^{n})=\sum _{x=1/K}^{A}({n \choose 1}{\frac {x^{n-1}}{K}}-{n \choose 2}{\frac {x^{n-2}}{K^{2}}}+{n \choose 3}{\frac {x^{n-3}}{K^{3}}}-...+/-{\frac {1}{K^{n}}})$

leads to 2 new sum properties for sum of polynomials lead f.ex. to this equalities... it seems no mathematician want to admit...

$A^{3}=\sum _{1}^{A}3X^{2}-3X+1=\sum _{x=1/K}^{A}{\frac {3x^{2}}{K}}-{\frac {3x}{K^{2}}}+{\frac {1}{K^{3}}}=\sum _{x=A/B}^{B}{\frac {3Ax^{2}}{B}}-{\frac {3xA^{2}}{B^{2}}}+{\frac {A^{3}}{B^{3}}}$

or

$A^{3}=\sum _{x=A/B}^{B}{\frac {3Ax^{2}}{B}}-{\frac {3xA^{2}}{B^{2}}}+{\frac {A^{3}}{B^{3}}}=\sum _{X=1}^{B}{\frac {3A}{B}}\left({\frac {A}{B}}X\right)^{2}-{\frac {3A^{2}}{B^{2}}}\left({\frac {A}{B}}X\right)+{\frac {A^{3}}{B^{3}}}$

That onto the Right Hand of Fermat the Last let one write:

$C^{3}-B^{3}=\sum _{x=1/K}^{C-B}{\frac {3(x+B)^{2}}{K}}-{\frac {3(x+B)}{K^{2}}}+{\frac {1}{K^{3}}}$

$=\sum _{x={\frac {C-B}{A}}}^{C-B}\left({\frac {3(C-B)(x+B)^{2}}{A}}-{\frac {3(C-B)^{2}(x+B)}{A^{2}}}+{\frac {(C-B)^{3}}{A^{3}}}\right)$

$=\sum _{X={\frac {(C-B)A}{C-B}}=1}^{{\frac {(C-B)A}{C-B}}=A}{\frac {3(C-B)(X{\frac {C-B}{A}}+B)^{2}}{A}}-{\frac {3(C-B)^{2}(X{\frac {C-B}{A}}+B)}{A^{2}}}+{\frac {(C-B)^{3}}{A^{3}}}$

so:

$C^{3}-B^{3}=\sum _{X=1}^{A}{\frac {3(C-B)(X{\frac {C-B}{A}}+B)^{2}}{A}}-{\frac {3(C-B)^{2}(X{\frac {C-B}{A}}+B)}{A^{2}}}+{\frac {(C-B)^{3}}{A^{3}}}$

And also:

$C^{3}-B^{3}=\sum _{x={\frac {1}{K}}}^{A}{\frac {3(C-B)({\frac {C-B}{A}}x+B)^{2}}{AK}}-{\frac {3(C-B)^{2}\cdot ({\frac {C-B}{A}}x+B)}{(AK)^{2}}}+{\frac {(C-B)^{3}}{(AK)^{3}}}=$

$C^{3}-B^{3}=\sum _{x={\frac {1}{A}}}^{A}{\frac {3(C-B)({\frac {C-B}{A}}x+B)^{2}}{A^{2}}}-{\frac {3(C-B)^{2}\cdot ({\frac {C-B}{A}}x+B)}{(A^{2})^{2}}}+{\frac {(C-B)^{3}}{(A^{2})^{3}}}=$

$C^{3}-B^{3}=\sum _{X=1}^{A^{2}}{\frac {3(C-B)({\frac {C-B}{A^{2}}}X+B)^{2}}{A^{2}}}-{\frac {3(C-B)^{2}\cdot ({\frac {C-B}{A^{2}}}X+B)}{(A^{2})^{2}}}+{\frac {(C-B)^{3}}{(A^{2})^{3}}}=$

I'm sitting on the river's border waiting for mathematicians define the mute index, and all of you following them...

Change "natural numbers" to "positive integers" in lede

The lede currently says

For example, summation of the first 100 natural numbers may be written as 1 + 2 + 3 + 4 + ⋯ + 99 + 100. Otherwise, summation is denoted by using Σ notation, where ${\textstyle \sum }$ is an enlarged capital Greek letter sigma. For example, the sum of the first n natural numbers can be denoted as ${\textstyle \sum _{i=1}^{n}i.}$

"Natural numbers" should be changed to "positive integers". Two reasons for this:

1. Many definitions, including the official standard ISO 80000-2, include 0 in the natural numbers. "Natural numbers" may or may not include 0, while "positive integers" always excludes 0. A more precise term is preferable to a less precise one. Why use an ambiguous term when an unambiguous one exists?

2. The rest of the article (see the section titled "Powers and logarithm of arithmetic progressions") also uses the convention of including 0 in the natural numbers.

User D.Lazard has insisted on reverting this constructive edit, without providing a justification. Their actions suggest WP:OWNBEHAVIOR. 2001:569:7F68:BF00:1967:F693:74B7:F460 (talk) 21:39, 3 November 2021 (UTC)

There no WP:OWNBEHAVIOR here, as your change has been reverted by two different editors, none of which being the author of the disputed sentence. On the other hand there is a clear problem of WP:Edit warring, since you tried 4 times to make the same change.

ISO is not and has never been a standard for mathematics. It is not an official standard, as ISO is a private company. However, ISO is commonly used as a standard in engineering. This article is not about engeenering, so the reference to ISO is irrelevant.

MOS:MATH#Article introduction says "The lead should, as much as possible, be accessible to a general reader, so specialized terminology [...] should be avoided". Here "positive integer" is a (mathematical) specialized terminology, as "positive" and "integer" are taught to kids a long time after they know natural numbers.

The sentence, as it is currently, is absolutely not ambiguous, as I do not know anybody who understand "the 100 first natural numbers" as not containing 100. Moreover, in the case of a doubt, this is clarified by the formula that follows. So, the unneeded use of a technical terminology that you suggest is a form of pedantry.

Your reference to the rest of the article is a fallacy, as "positive integer" is used once in a formula where excluding zero is fundamental, while "natural number" is used three time, without indicating whether zero is included, except for the third formula that remains true if the term of index 0 is ommitted. D.Lazard (talk) 10:02, 4 November 2021 (UTC)

Response:

It is not an official standard, as ISO is a private company.

ISO is an independent, non-governmental international organization with a membership of 166 national standards bodies.

However, ISO is commonly used as a standard in engineering. This article is not about engeenering, so the reference to ISO is irrelevant.

It is also used as a standard in chemistry, physics, and mathematics. See ISO 31-11 for an example.

MOS:MATH#Article introduction says "The lead should, as much as possible, be accessible to a general reader, so specialized terminology [...] should be avoided". Here "positive integer" is a (mathematical) specialized terminology, as "positive" and "integer" are taught to kids a long time after they know natural numbers.

1. The term "integer" is not "specialized terminology". "General reader" does not mean "preschooler".

2. The term "natural number" (as opposed to simply "number") is no less "technical" than "integer".

3. I linked it to the article on integers.

The sentence, as it is currently, is absolutely not ambiguous

It absolutely is ambiguous, since "natural numbers" may or may not include 0.

"positive integer" is used once in a formula where excluding zero is fundamental

Irrelevant.

"natural number" is used three time, without indicating whether zero is included

The two formulas I'm referring to do include 0. Underneath the summation symbol is $i=0$, meaning the summation starts at 0.

except for the third formula that remains true if the term of index 0 is ommitted

Irrelevant. It is not true in the general case that $\sum _{i=0}^{n}a_{i}=\sum _{i=1}^{n}a_{i}$. 2001:569:7F68:BF00:34:F758:DCF1:F531 (talk) 21:33, 4 November 2021 (UTC)

How about replacing "summation of the first 100 natural numbers" with "summation of natural numbers from 1 to 100"? However, in the sentence immediately after it, it says "1 + 2 + 3 + ... + 100", so I think it's clear even as it is now.--SilverMatsu (talk) 22:42, 4 November 2021 (UTC)

Relationship between summation and repeated multiplication

Defining a relationship between these two will be good. Yuthfghds (talk) 17:23, 10 July 2023 (UTC)

Which relationship have in mind? For the relationship between repeated addition and multiplication, see the second paragraph of Multiplication and Multiplication and repeated addition. D.Lazard (talk) 19:39, 10 July 2023 (UTC)