Timeline for Families of subsets containing every singleton as an intersection
Current License: CC BY-SA 3.0
9 events
| when toggle format | what | by | license | comment | |
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| Feb 10, 2012 at 16:26 | vote | accept | Johnny | ||
| Feb 9, 2012 at 21:50 | answer | added | Noah Stein | timeline score: 7 | |
| Feb 9, 2012 at 21:48 | comment | added | Johnny | Better and better ... thanks, Andreas. It seems like a silly question that I started with now. | |
| Feb 9, 2012 at 21:46 | history | edited | Johnny | CC BY-SA 3.0 |
added 45 characters in body; deleted 98 characters in body
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| Feb 9, 2012 at 21:44 | comment | added | Andreas Blass | Let $X$ be the set of vertices of a $d$-dimensional cube. Let $F$ be the set of faces of the cube (each face being considered as just the set of its vertices). Then $|X|=2^d$ while $|F|$ is only $2d$. | |
| Feb 9, 2012 at 21:44 | comment | added | Johnny | Thanks Gjergji - this can easily be generalized for $n=2m+1$ to give a family of size $m+2$. So new question: can anyone find a better construction than this? | |
| Feb 9, 2012 at 21:39 | comment | added | Gjergji Zaimi | $\lbrace (1,2,5),(2,3),(3,4,5),(1,4)\rbrace$ | |
| Feb 9, 2012 at 21:37 | history | edited | Johnny | CC BY-SA 3.0 |
added 4 characters in body; deleted 1 characters in body; deleted 2 characters in body
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| Feb 9, 2012 at 21:29 | history | asked | Johnny | CC BY-SA 3.0 |