Timeline for What is the minimum number of covering subsets?
Current License: CC BY-SA 2.5
4 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Sep 9, 2010 at 23:04 | answer | added | Sergei Ivanov | timeline score: 2 | |
| Sep 9, 2010 at 22:55 | answer | added | mathkid | timeline score: 0 | |
| Sep 9, 2010 at 22:26 | comment | added | Max Horn | If T is empty, then $C \cdot |T| = 0$ which cannot exceed $|S_{i_1} \cup S_{i_2} \cup \cdots \cup S_{i_C}|$. So maybe you want to assume $T$ is not empty? Or make the inequality non-sharp? Likewise, if $T=\\{1,\cdots,N\\}$ then $|T| = N = |S_{i_1} \cup S_{i_2} \cup \cdots \cup S_{i_C}|$ so that would preclude the possibility $C=1$. Maybe this is intentional, though? Moreover, if $C>N$ then your inequality is automatically satisfied (except for the edge cases I mentioned above). Again, possibly intentional? Perhaps you could clarify a bit what you intended in these edge cases? | |
| Sep 9, 2010 at 20:38 | history | asked | mathkid | CC BY-SA 2.5 |