Subject: Re: [HM] symbol for infinity
From: Bernd Buldt (Bernd.Buldt@uni-konstanz.de)
Date: Mon Jan 03 2000 - 08:59:24 EST
> I'm looking for the origin of the symbol for infinity (oo).
> Who introduced this notation? And is there any signification?
dear eric,
i've once looked it up myself and found in moritz cantor's
"vorlesungen ueber geschichte der mathematik", vol. 2 (1965 reprint
of the 2nd ed. 1900) the following two facts:
(i) p. 794: that descartes used in his geometry a sign very close to
the inf-symbol "oo" to denote equality (which we all knew before, i
think, but, and maybe this is new, cantor mentions in addition that
this symbol should resemble the intertwined letters "ae" in reverse
order), and
(ii) p. 820: that john wallis was the first to use the 'laying eight'
as an inf-symbol; cf. his "tractatus de secionibus conicis nova
methodo expositis (1655), in: opera mathematica (oxford 1699) I,
291-354, here p. 297: " esto oo [= inf-symbol] nota numeri infiniti".
regards, bernd
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