English

The probability that a random triple of dice is transitive

Combinatorics 2025-02-13 v2 Probability

Abstract

An nn-sided die is an nn-tuple of positive integers. We say that a die (a1,,an)(a_1,\dots,a_n) beats a die (b1,,bn)(b_1,\dots,b_n) if the number of pairs (i,j)(i,j) such that ai>bja_i>b_j is greater than the number of pairs (i,j)(i,j) such that ai<bja_i<b_j. We show that for a natural model of random nn-sided dice, if A,BA, B and CC are three random dice then the probability that AA beats CC given that AA beats BB and BB beats CC is approximately 1/2. In other words, the information that AA beats BB and BB beats CC has almost no effect on the probability that AA beats CC. This proves a statement that was conjectured by Conrey, Gabbard, Grant, Liu and Morrison for a different model.

Keywords

Cite

@article{arxiv.2211.16156,
  title  = {The probability that a random triple of dice is transitive},
  author = {D. H. J. Polymath},
  journal= {arXiv preprint arXiv:2211.16156},
  year   = {2025}
}