# Talk:Double exponential function

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Field:  Analysis

## Contents

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)

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 ${\displaystyle a^{b^{x}}}$ is not explained in this article, but it is commonly agreed upon (at least among professional mathematicians) that ${\displaystyle a^{b^{x}}}$ should be read as ${\displaystyle a^{(b^{x})}}$. 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)