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Topic: etymology of "totient" ?
Replies: 15   Last Post: Apr 10, 1997 1:09 PM

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 Robert Israel Posts: 11,902 Registered: 12/6/04
Re: etymology of "totient" ?
Posted: Apr 10, 1997 1:09 PM

In article <5ih9ed$24v$1@nntp.ucs.ubc.ca>, israel@math.ubc.ca (Robert Israel) writes:
|> Euler never used that word. J.J Sylvester coined it around 1883, and
|> he was writing in English. He doesn't say where he took it from, but it could
|> just as plausibly be from the letter "t" (Sylvester used \tau n for \phi(n))
|> + the ending of "quotient".

Correction. Sylvester first used the word in "On Certain Ternary Cubic-Form
Equations", Amer. J. Math 2 (1879) 280-285, 357-393, in Sylvester's Collected
Mathematical Papers vol. III p. 321. He writes:
"The so-called \phi function of any number I shall here and hereafter designate
as its \tau function and call its Totient".

My suggestion that the "t" came from "tau" was rather silly, and in fact
Sylvester says (in vol. IV p. 589 of his Collected Mathematical Papers)
"I am in the habit of representing the totient of n by the symbol \tau n,
\tau (taken from the initial of the word it denotes) being a less hackneyed
letter than Euler's \phi, which has no claim to preference over any other letter
of the Greek alphabet, but rather the reverse".

BTW, according to Dickson's "Theory of Numbers", it seems Euler didn't use
\phi either, but rather \pi, and Gauss introduced \phi (Disq. Arith., article 38).

Robert Israel israel@math.ubc.ca
Department of Mathematics (604) 822-3629
University of British Columbia fax 822-6074

Date Subject Author
3/20/97 Ko-Wei Lih
3/20/97 Dr. Eric Wingler
3/20/97 Robert Israel
3/20/97 Eric Gindrup
3/22/97 Kurt Foster
4/4/97 Walter Nissen
4/6/97 Geoff Hagopian
4/8/97 Terry Moore