I would like to know whether every ordinal $\alpha$ has a well-defined "next limit ordinal", i.e. a least limit ordinal $\beta$ such that $\beta > \alpha$.
I understand from this discussion that probably not every limit ordinal is such a "next" one. E.g., I assume that $\omega^2$ is the first limit ordinal which is not a "next limit ordinal". But I am still interested whether there is a way to go "from any ordinal $\alpha$ to the next limit ordinal $\beta > \alpha$".
To summarize, my questions are:
- Does every ordinal have a well-defined "next limit ordinal"?
- Are there limit ordinals (except 0) which are not a "next limit ordinal"? Is $\omega^2$ the first limit ordinal of that kind?
- Is the "next limit ordinal" of $\alpha$ always $\alpha + \omega$?
Update: Questions 1. and 3. are answered below. Question 2. is still unanswered.