Timeline for Intersecting group orbits
Current License: CC BY-SA 3.0
4 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Aug 14, 2016 at 12:23 | comment | added | Sean Eberhard | I needed this nice fact again today. For reference, here is an argument I find easier to remember. Fix a set $A$ as above, and pick $g$ uniformly at random from $G$. If $A$ is intersecting then $A \cap gA$ is always nonempty, so there exists $x,y \in A$ such that $gx = y$. The probability of this event is $1/n$, and there are $k^2$ such events, so $k^2/n \geq 1$. | |
| Mar 10, 2012 at 17:39 | vote | accept | Sean Eberhard | ||
| Mar 10, 2012 at 17:05 | comment | added | Andreas Blass | This, along with the projective plane example, was actually going to be in a paper I'm writing. Fortunately, the main topic of the paper is something else, so the paper won't lose much by omitting this. | |
| Mar 10, 2012 at 17:02 | history | answered | Andreas Blass | CC BY-SA 3.0 |