Friday, 23 August 2013

Proper Subset of an Infinite Set is Equinumerous to the Set Containing It

Proper Subset of an Infinite Set is Equinumerous to the Set Containing It

I noticed that there is a question about $S$ being denumerable, which
implies $S$ is equinumerous with a proper subset of itself, but what about
an infinite set? That is, how to do I prove that every infinite set is
equinumerous with a proper subset of itself?

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