If you have an infinite set $X$, how do you prove that $$ $X$ $\times$ $X$ $$=$$ $X$ $$. I believe AC is needed but I don't quite see how to write the proof. Thanks.
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closed as too localized by Martin Brandenburg, Chandan Singh Dalawat, Robin Chapman, Simon Thomas, Ryan Budney Dec 11 '10 at 14:33
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