Zulip Chat Archive

Stream: Is there code for X?

Topic: a well-ordered subset of \R is countable


view this post on Zulip Kenny Lau (Jun 11 2020 at 06:55):

do we know that a well-ordered subset of \R is countable?

view this post on Zulip Kenny Lau (Jun 11 2020 at 06:57):

proof: successor function exists

view this post on Zulip Kevin Buzzard (Jun 11 2020 at 07:34):

Conversely I believe any countable ordinal can be order-embedded in R

view this post on Zulip David Wärn (Jun 11 2020 at 07:56):

We should at least have Kevin's converse result soon, as a special case of "any countable order embeds in any dense order"


Last updated: May 07 2021 at 21:10 UTC