Re: Ten points in a square



"Zdislav V. Kovarik" <kovarik@xxxxxxxxxxx> wrote:
It is a standard exercise on Pigeonhole Principle to prove:

If you place 10 distinct points in a square of side 1, then at least
two points will have distance no more than sqrt(2)/3 (about 0.4714).

My question: This number is an upper bound for the minimum
positive distance. Has anyone found the least upper bound?

(It is at least 1/3, just place the points at lattice points
with stepsize 1/3. With slightly more effort, one can replace
1/3 by sqrt(2)/(2*sqrt(2)+1), about 0.3694.)

By the way, tens of millions of pseudorandom experiments have
not exceeded 0.32.

It is 0.421..., which follows from the packing of ten unit circles, proven
optimal, shown at <http://www.stetson.edu/~efriedma/cirinsqu/>.

David W. Cantrell
.



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