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Chris Ormell's article
Published online by Cambridge University Press: 23 January 2015
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In [1], Chris Ormell raised a question about the uncountability of the real numbers. Ormell affirmed that only a countable collection of numbers may be defined by a finite number of words, a notion that stems from a letter of Richard (1905), reproduced in [2, p. 142]. This appears to conflict with Cantor's proof (1874) of the uncountability of the reals [3, p. 839]. Poincaré, whom Ormell claims as a witness in his defence, said ‘Now as is well known, Cantor proved that the continuum is not denumerable; this contradicts the proof of Richard. The question therefore arises which of the two proofs is correct. I maintain that they are both correct and that the contradiction is only apparent.’ [3, p. 1072] Poincaré then supplied a new proof that the points on an interval are not countable.
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