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9:56 AM
Some discussions on definition of ordinals and cardinals in the main chat room:
in Mathematics, 3 hours ago, by Leaky Nun
So we have:
- $\omega_1$, the union of all countable ordinals
- $\aleph_1$, the first uncountable cardinal
Now, how are $\omega_1$ and $\aleph_1$ equal? What axioms/theorems are needed to prove that they are equal?
 

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