New posts in Ordinals

Countable ordinals are embeddable in the rationals $\Bbb Q$ -- proofs and their use of AC

How many epsilon numbers $<\omega_1$ are there?

When does ordinal addition/multiplication commute?

Is there an axiomatic approach to ordinal arithmetic?

Intuition for $\omega^\omega$

How to define countability of $\omega^{\omega}$ and $\omega_1$? in set theory?

How do I show there isn't an order isomorphism b/w the two sets $\{1, 2, 3,...\}$ and $\{1, 2, 3, ..., \omega \}$

Operations on ordinal numbers

How is $\epsilon_0$ countable?

Uncountability of countable ordinals