Talk:Egyptian fraction

This is the talk page for discussing improvements to the Egyptian fraction article.
This is not a forum for general discussion of the article's subject.

Put new text under old text. Click here to start a new topic.
New to Wikipedia? Welcome! Learn to edit; get help.

Article policies

Find sources: Google (books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL

Archives: 1, 2: 12 months

Ancient Egypt

This article is within the scope of WikiProject Ancient Egypt, a collaborative effort to improve the coverage of Egyptological subjects on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.Ancient EgyptWikipedia:WikiProject Ancient EgyptTemplate:WikiProject Ancient EgyptAncient Egypt

???

This article has not yet received a rating on the project's importance scale.

WikiProject Ancient Egypt to-do list:

Needed articles.

We should have an article on every pyramid and every nome in Ancient Egypt. I'm sure the rest of us can think of other articles we should have.

Cleanup.

To start with, most of the general history articles badly need attention. And I'm told that at least some of the dynasty articles need work. Any other candidates?

Standardize the Chronology.

A boring task, but the benefit of doing it is that you can set the dates !(e.g., why say Khufu lived 2589-2566? As long as you keep the length of his reign correct, or cite a respected source, you can date it 2590-2567 or 2585-2563)

Stub sorting

Anyone? I consider this probably the most unimportant of tasks on Wikipedia, but if you believe it needs to be done . . .

Data sorting.

This is a project I'd like to take on some day, & could be applied to more of Wikipedia than just Ancient Egypt. Take one of the standard authorities of history or culture -- Herotodus, the Elder Pliny, the writings of Breasted or Kenneth Kitchen, & see if you can't smoothly merge quotations or information into relevant articles. Probably a good exercise for someone who owns one of those impressive texts, yet can't get access to a research library.

Mathematics Mid‑priority

	Mathematics portal This article is within the scope of WikiProject Mathematics, a collaborative effort to improve the coverage of mathematics on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.MathematicsWikipedia:WikiProject MathematicsTemplate:WikiProject Mathematicsmathematics
Mid	This article has been rated as Mid-priority on the project's priority scale.

Dyadic rational definition

Are dyadic rationals the set of numbers of the form 1/2^n as this page says or m/2^n as the dyadic rational page says? Dakane2 (talk) 04:36, 10 May 2011 (UTC)[reply]

The m/2^n definition is the correct one. But the numbers 1/2^n are examples of dyadic rationals (just not all possible dyadic rationals) and using sums of them any dyadic rational can be formed. —David Eppstein (talk) 04:46, 10 May 2011 (UTC)[reply]

Incorrect use of the symbol Omega

(To David Eppstein). Look now. I have been doing and publishing research in analytic number theory for forty years, and one of the main topics I studied is Omega results. I know exactly what the symbol means. It is never used to replace a number. You can write that the number of terms needed = Omega(loglogx), meaning that there is a relation between the number of terms and the function loglogx, or alternately that the function counting the number of terms belongs to a certain set of functions. But you cannot use Omega(loglogx) in order to denote a number of objects. It is just never done in the literature. Also, there is no need to be insulting in your comments. Sapphorain (talk) 07:02, 19 April 2016 (UTC)[reply]

How could "the number of terms needed = Omega(loglogx)" be any different than "the number of terms needed is Omega(loglogx)"? Especially given that "=Omega" is in my experience usually pronounced out loud as "is Omega" as It's not actually Intended as an equalIty? But I admIt that my experIence wIth Omega notatIon Is In theoretIcal computer scIence and combInatorIcs, where the conventIons may be dIfferent (certaInly the defInItIon of Omega Is somewhat dIfferent) and Its usual use Is Indeed to lower bound (not denote) a number of objects, In exactly the same way that O-notatIon Is used In the same paragraph to upper bound the same number of objects. ThIs artIcle Is not partIcularly analytIc, but It Is number theory, so I suppose that takes precedence. —David Eppstein (talk) 07:21, 19 April 2016 (UTC)[reply]

Alternative modern notation?

I don't know whether this sort of notation is outdated, but I have often come across unit fractions being represented as the number with a dot over it. For example, 1⁄2 is written ${\dot {2}}$ , 1⁄10 is written ${\dot {10}}$ , and so on. (Though I am not sure whether there is a way to express a 2⁄n fraction using this sort of notation.) I am just pointing this out because I don't see any mention of it in the article yet it seems very common. 98.115.103.26 (talk) 16:44, 19 June 2017 (UTC)[reply]

Can you point me to a published source (like a book or journal article) that uses this notation for Egyptian fractions? Because I don't recall seeing it, but that doesn't mean it's not out there somewhere. —David Eppstein (talk) 16:53, 19 June 2017 (UTC)[reply]

Sorry, I think I remember seeing it in some translation or transliteration of one of the Egyptian mathematical texts, but I can't seem to find it. Guess it wasn't as common as I thought. Perhaps it was just one author doing it his own way rather than following the standard convention. 98.115.103.26 (talk) 19:34, 19 June 2017 (UTC)[reply]

All right, I still haven't been able to find a source, but I did come across a few images saved on my hard drive and was able to locate them online using Google's image search:

The first is a transcription and transliteration of problem 56 from the Rhind Papyrus: https://i0.wp.com/farm9.staticflickr.com/8081/8286659490_1f53a86564_o_d.jpg That was on some guy's blog, but supposedly it's originally from August Eisenlohr. If so, I'm guessing it's outdated? He was from the 19th century...

The second is a facsimile of problem 50 from the Rhind Papyrus, with transcription and transliteration: https://i.warosu.org/data/sci/img/0080/27/1461531495325.jpg This one has been posted and reposted on several blogs. No idea where it's originally from.

I notice on both of these the transliteration (letter-for-letter) goes from right to left. Seems kind of bizarre... I've never seen anyone do it that way before. But then again, I'm not an egyptologist.

But anyway, you can see in both of those that there's a dot above the numeral. So apparently at least some people transliterated it that way at some point. But I guess it's not that common... 98.115.103.26 (talk) 02:36, 23 June 2017 (UTC)[reply]

Erdős–Graham Conjecture

Is the Erdős–Graham Conjecture stated correctly? If the sets contain unit fractions, then their reciprocals are natural numbers greater than 1. It would be pretty hard to find a set of those that sum to 1. I think we must either define the sets as containing natural numbers greater than 1, or take out the "reciprocals". Sicherman (talk) 03:53, 30 October 2017 (UTC)[reply]

Yes. Changed to integers instead of unit fractions. Thanks for catching this. —David Eppstein (talk) 05:02, 30 October 2017 (UTC)[reply]

Glad to help! But you omitted the critical phrase "greater than 1." I have supplied it. Sicherman (talk) 02:07, 31 October 2017 (UTC)[reply]

History sections seem substantially inadequate

From what I can tell "Egyptian fractions" were the main representation used throughout the Mediterranean and Greek- and Arabic-writing world throughout the medieval period (coexisting with Mesopotamian sexagesimal arithmetic), only displaced late by "common fraction" techniques using Hindu–Arabic numerals. This article hand-waves thousands of years of history with not even a sentence as "continued to be used in Greek times and into the Middle Ages", with organization that forestalls future expansion about it. The substantial focus on Fibonacci per se, without any mention of e.g. medieval Arabic sources, seems like a "neutral point of view" problem. More generally, the focus on algorithms expressed in modern notation pulls the subject from context and gives an anachronistic impression of its substance. The approach seems appropriate for a modern math book, but not really sufficient for a general encyclopedia. –jacobolus (t) 13:51, 26 October 2023 (UTC)[reply]

Example source: Saidan, A. S. (1974), "The Arithmetic of Abū'l-Wafā'", Isis, 65 (3): 367–375, JSTOR 228959. –jacobolus (t) 15:55, 26 October 2023 (UTC)[reply]