Timeline for Size of antichains in powerset of $\mathbb N$
Current License: CC BY-SA 4.0
13 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| May 27 at 14:49 | vote | accept | E. Z. L. | ||
| May 26 at 17:51 | comment | added | Todd Trimble | @SaúlRM Yes indeed, it's generally better to give an answer than just to answer in the comments, if the question belongs on the site. (I'd say this question is borderline, in the sense that it would have been widely considered acceptable for MO years ago, but not as much anymore.) Despite the incongruity, I wouldn't say you did anything wrong. What I would consider wrong is to both vote to close and to answer, but you didn't do that. Hope this all makes sense! | |
| May 26 at 10:03 | comment | added | Saúl RM | @ToddTrimble Other time I answered a question similar to this one in the comments and I was told to post it as an answer if it was an answer to the question (also, it is the other way around, first I answered and then I saw the MSE duplicate and posted the comment) | |
| May 26 at 3:26 | comment | added | Timothy Chow | @JoelDavidHamkins Sure. I'm just telling an anecdote. | |
| May 26 at 3:26 | comment | added | Joel David Hamkins | But Timothy, the study of almost disjoint families is far older than that. | |
| May 26 at 3:23 | comment | added | Timothy Chow | Problem B-4 of the 1989 Putnam asked, "Can a countably infinite set have an uncountable collection of non-empty subsets such that the intersection of any two of them is finite?" (I suspect they copied this problem from Donald Newman's book, A Problem Seminar, since Problem A-4 from that year also appears in the same book.) I still remember Greg Landweber explaining to us afterward, "Take any real number, say $\pi$, and from it construct the set $\{3, 31, 314, 3141, 31415, \ldots\}$." By the way, another nice puzzle is, can there be a chain in $\mathcal{P}(S)$ of continuum cardinality? | |
| May 26 at 0:46 | comment | added | Todd Trimble | It's slightly incongruous to say that a question belongs somewhere else, and then to answer it as though it belongs here. | |
| May 25 at 23:59 | comment | added | Joel David Hamkins | Here is an essay I had written about various features to be found in the lattice of sets of natural numbers: infinitelymore.xyz/p/lattice-of-sets-of-natural-numbers. | |
| May 25 at 4:56 | review | Close votes | |||
| Jun 3 at 3:02 | |||||
| May 25 at 1:48 | comment | added | Saúl RM | It seems the question is already answered here. Also, a question like this is more appropriate for Mathematics Stack Exchange | |
| May 25 at 1:39 | answer | added | Saúl RM | timeline score: 7 | |
| S May 25 at 1:36 | review | First questions | |||
| May 25 at 1:39 | |||||
| S May 25 at 1:36 | history | asked | E. Z. L. | CC BY-SA 4.0 |