Timeline for Cover the $n$-disc irredundantly with $n+1$ open sets. Suppose that the $(n+1)$-fold intersection is empty. Then is some $n$-fold intersection empty?
Current License: CC BY-SA 4.0
4 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Apr 11 at 1:22 | vote | accept | Tim Campion | ||
| Apr 11 at 1:17 | comment | added | Tim Campion | Oh interesting. In my case, my disk is actually a simplex, and I do in fact have the $i$th vertex of the simplex in the $i$th open set of the cover, so I’m also very interested in the lemma! | |
| Apr 11 at 1:15 | comment | added | Saúl RM | I think the lemma I use or some generalization of it was well known in algebraic topology, if someone can provide a reference I could just cite it. Edit: It seems the version for closed sets is the Knaster–Kuratowski–Mazurkiewicz lemma | |
| Apr 11 at 1:13 | history | answered | Saúl RM | CC BY-SA 4.0 |