Talk:Double exponential function

Further reading

Just a note for eagle-eyed editors out there: the reading reference I gave has a different date than the text in the page linked to claims. The page is wrong, the correct date is 1973. This can be verified with an index of Fibonacci Quarterly if desired. CRGreathouse (t | c) 08:07, 22 December 2006 (UTC)

Why is googleplex large?

This article needs to explain the order of calculation of exponentials. It is not made clear here why a googleplex is larger than 10 to the 1000th. —Preceding unsigned comment added by 88.65.219.136 (talk) 11:27, 9 June 2010 (UTC)

Because a googolplex (note the spelling) is 10¹⁰¹⁰⁰, and 10 to the 1000th is just 10¹⁰⁰⁰. Take the common logarithm of both sides and you get 10¹⁰⁰ and 1000 = 10³ respectively: the former is obviously much larger than the latter. (Or if it isn't obvious yet, do it again to get 100 and 3, where there can be no doubt as to which is larger.) You do power towers from the right, so 10¹⁰¹⁰⁰ means 10^(10100) and not (10¹⁰)¹⁰⁰ (which indeed equals 10¹⁰⁰⁰). Double sharp (talk) 04:55, 30 August 2015 (UTC)

I made some modifications to reflect the correct interpretation of powers of powers, but the error is repeated across the whole page... —Preceding unsigned comment added by 88.65.219.136 (talk) 11:37, 9 June 2010 (UTC)

Data structures

Most of the contain of the section "Data structures" is irrelevant to this article. If it is notable enough for Wikipedia, it should appear in separate articles in category:Data structures. What is relevant for this page is simply: "Double exponential sequences appear naturally in several data structures and searching algorithms, such as Iacono's working set structure, Optimal in-place static searching, Optimal dynamic searching, Doubly exponential level search on x-fast tries". Such a sentence will be meaningful only when, at least, one of the red links will become blue. Therefore I'll remove this section until that. — D.Lazard (talk) 08:58, 26 April 2012 (UTC)

Article is plain wrong

Sorry for telling it straigth away. The function f(x) = A ^ B ^ x equals the function f(x) = A ^ (B * x). Try it in a spreadsheet, if you don't believe it. A double exponential function is just an exponential function as any other. The reason that f(x) = A ^ (B * x) grows faster than f(x) = A ^ x is that we are multiplying the exponent by a constant B. The statement, that a double exponential function is growing faster than an exponential function just doesn't make any sense. Mad4linux (talk) 10:23, 22 November 2013 (UTC)

Observe that the two functions f(x) = A ^ (B ^ x) and g(x) = (A ^ B)^x are not identical. The notation $a^{b^{x}}$ is not explained in this article, but it is commonly agreed upon (at least among professional mathematicians) that $a^{b^{x}}$ should be read as $a^{(b^{x})}$. The article about Fermat number, which is linked from exponential function, is more explicit about the meaning of the notation. Hermel (talk) 19:42, 27 November 2013 (UTC)

I've edited the article, so that the meaning of the notation is explained. Hermel (talk) 19:48, 27 November 2013 (UTC)

Double or doubly exponential?

The two terms are almost equally represented in the article, with their clustering suggesting different editors prefer one or the other version. Shouldn't they be unified, possibly with some explanation in the lead para about their equivalence? CiaPan (talk) 15:46, 30 November 2018 (UTC)

Pretty much a linguistic distinction without a difference IMO. It looks like "doubly exponential" is used to describe expressions with stacked exponentials, as in the N(y) in the Theoretical biology section, while "double exponential" means a more specific function. In other words one phrase is used as an adjective and the other is used as a noun. Having both phrases makes sense in terms of readability; it does make the scope of the article a bit vague but with so little material to work with this seems harmless. --RDBury (talk) 22:11, 30 November 2018 (UTC)

I would say "double exponential". I don't think you would call its inverse "doubly logarithmic". I would say "It is a double exponential function" but "the function is doubly exponential". Bubba73 ^{You talkin' to me?} 01:16, 1 December 2018 (UTC)

I agree with Bubba. It should be “a double exponential function” (a function containing a double exponential) but “a function that is doubly exponential”. Loraof (talk) 21:33, 1 December 2018 (UTC)

Logarithmic notation

The article currently reads, "The inverse of the double exponential function is the double logarithm ln(ln(x))."

I'm not a mathematician, but should that read "log(log(x))"? Doesn't "ln" imply the natural log, log using the base e, which would imply that the a and b of the double exponential function as given woudl be equal to e? IAmNitpicking (talk) 16:04, 20 January 2022 (UTC)

Log log is probably better. Not a big deal, I changed it. - CRGreathouse (t | c) 21:31, 24 January 2022 (UTC)