MathOverflow is a question and answer site for professional mathematicians. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

In Rd, I have n > d+1 points. The mean distance between pairs of points is 1. How can I minimize the variance of the distances (equivalently, the mean squared distance)? I'm mainly interested in d ∈ {1,2,3} although I'd be curious if there were any patterns for larger values of d. As for values of n, I'm interested both in specific solutions for small values, and general patterns in larger values.

share|cite|improve this question
Pairs of distinct points, or all pairs of point? If the latter, do you count (y,x) separately from (x,y)? – Ricky Demer Aug 8 '10 at 6:51
Sorry, good point (no pun intended). I meant pairs of distinct points. – Robin Saunders Aug 8 '10 at 11:43
It's of small consequence how you count the points since, for fixed n, it will only scale the mean 1 by a constant, and this will not change the variance-minimizing configuration. What might be significant is whether you intend the arithmetic, geometric, harmonic, ... mean (only joking!). – John Bentin Aug 8 '10 at 12:18

For $d=1$, it is minimized by arithmetic progression.

share|cite|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.