David Chudzicki

Posts

Sorted by New

Wiki Contributions

Comments

Sorted by

(I'm one of Jeff's housemates.) Going to the grocery would violate our rules even if you could stay 6ft away, because it's inside.

I guess there's one market in our area that's (a) outside, with (b) careful distancing. Going there would be fine I think, but I don't know if any of us have.

There wasn't much but I'm working on resurrecting what there was. Maybe I'll get DNS fixed this weekend but for now: http://www.davidchudzicki.com.s3-website-us-east-1.amazonaws.com/

To add to the confusion, there are normally only two symbols for infinity to go around - ω and ∞

This post is the first I recall seeing ω used to refer to a cardinal. (The smallest infinite cardinal is usually called א‎₀.)

And I think hyperreals are probably a much less common topic than the other three, so at least we have different notation for the top three of these four notions (ω for the ordinal, א‎₀ for the cardinal, ∞ for the limit).

I'm not confident in this, but also: It looks to me like ω can be considered the same number in the ordinals, surreals, and hyperreals (since the surreals contain both of the other two). So I guess that's probably why we use the same notation, and why it's not really a serious ambiguity.