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A comment on Does infinity exist?. Parent comment

Re:Does infinity exist? by michaelcampbell on Saturday September 15, 2012 @01:38PM (#4526686)
Honest question here; is the phrase "same number of X and Y" equivalent mathematically to "the cardinality of X and the cardinality of Y are the same"? I was taught "no", since "number of" doesn't apply to any of the infinities.

But perhaps I was taught incorrectly, or I have misremembered.

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Re:Does infinity exist? by jgrahamc on Monday September 17, 2012 @04:15AM (#4531668)
Well, Cantor's big thing was partly that he extended cardinality to infinite sets (http://en.wikipedia.org/wiki/Cardinal_number). The first infinite cardinal \aleph_0 is the cardinality of the natural numbers.
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