[HM] idempotent

Randy K. Schwartz (rschwart@schoolcraft.cc.mi.us)
Sun, 15 Nov 1998 20:00:39 -0500

I note on Jeff Miller's web page "Earliest Known Uses...", the
following entry:

IDEMPOTENT and NILPOTENT were used by Benjamin Peirce (1809-1880) in
1870 in American Journal of Mathematics (1881): "When an
expression...raised to a square or higher power...gives itself as the
result, it may be called idempotent" (OED2).

This raises at least three questions:
(0) Is that the correct spelling of Ben's last name?
(1) Which is the correct date: 1870 or 1881?
(2) As far as I can tell, the currently universally accepted
definition of idempotent is that which would be obtained from Pierce's
by striking the phrase "or higher power".
In using the conjunction "or", did Pierce mean to categorize as
an idempotent any element satisfying, say, (e)(e)(e) = e ? And if so,
when and how did the narrower usage come about?

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Prof. Randy K. Schwartz
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