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editI'm dubious about the words 'simplest form,' since I don't see how we can call 9 the 'simplest form' of 2781. How is 9 a form of 2781?! Usually when we say "simplest form" (reducing fractions, simplifying algebraic expressions, etc.), we're making only a cosmetic change. Changing 2781 into 9 is more than cosmetic. Doops 16:49, 30 Apr 2004 (UTC)
- Presumably the term persistence can be used in other ways, other than referring to digital roots by addition or multiplication. Let me try and fix that sentence. Dysprosia 00:40, 1 May 2004 (UTC)
- Of course, the wording simplest form is too fuzzy; instead, it is a fixed point of the operation, i.e. a number on which the operation yields the same number again. I have majorly rewritten the article to account for that. By the way, I don't think the term persistence of a number is used in mathematics for anything but the additive and multiplicative persistence. Therefore, I think we can get rid of the overly abstract first sentence and just say what additive and multiplicative persistence is. Comments? --Yogi de 22:17, 5 Jun 2005 (UTC)
Reading this article is a good example of the need for some way of easily reading large digits if one wants to quickly know the size. I prefer commas, 234,234,234,234.0234, but I don't mind spaces 234 234 234 234 023 4, as either is better than 234234234234.0234. Without such a visual aid, it is annoying and I suppose stubborn persistence not to make a decision on whether or not to use commas or spaces, use ISO or not. —Preceding unsigned comment added by 75.55.127.248 (talk) 03:05, 31 July 2009 (UTC)
Are any results known for non-decimal bases? Double sharp (talk) 10:19, 20 June 2014 (UTC)
Clarifying the simple algorithm for calculating the persistence of a number.
editIn the article, it says "By cleverly using the specific properties of numbers in this sequence, the above terms can be calculated in a fraction of a second.". Is it possible if a citation to this algorithm, or a brief explanation could be provided? I think that would provide a clearer understanding of the mathematics to the reader. — Preceding unsigned comment added by Svdsps (talk • contribs) 20:55, 23 January 2017 (UTC)
- I agree that this sentence was not very helpful. I replaced it by a more precise description of the properties that help speed the search. —David Eppstein (talk) 23:07, 23 January 2017 (UTC)
- Oh yee of uncertain faith, to wit:
function multiplicativePersistence(a,b){for(var d=0,f=a.toString(b);console.log(d+":"+f),!(1>=f.length);)f=[...f].map(h=>parseInt(h,b)).reduce((h,i)=>h*i,1).toString(b),d++;return d} multiplicativePersistence(277777788888899,10);
WurmWoodeT 14:34, 29 March 2019 (UTC)
- Oh yee of uncertain faith, to wit:
title
editi think the current title, "Persistence of a number", is a bit too wordy and i propose moving it to "Persistence (mathematics)"