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Lonely Runner Conjecture


The lonely runner conjecture asserts that, for any n distinct positive integers v_1,...,v_n, there is a real number t such that

 min_(1<=j<=n)||tv_j||>=1/(n+1),

where ||x|| denotes distance to the nearest integer, not a vector norm. In the running interpretation, a stationary runner and n other runners move on a unit-circumference circle, and every runner should at some time be at distance at least 1/(n+1) from all the others (Hu and Jing 2026).

Hu and Jing (2026) proved that there is an absolute constant c>0 such that, for every n>=2 and every such speed set,

 max_(t in R)min_(1<=j<=n)||tv_j||>(1+c)/(2n).

This is a fixed proportional improvement over 1/(2n), not the full conjectured bound. Hu and Jing (2026) describe ChatGPT assistance with checking and making arguments rigorous and with refinements, while attributing the strategy and framework to the authors.


See also

Circle, Nearest Integer Function

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References

Hu, X. and Jing, Y. "Near Optimal Gap in the Lonely Runner Conjecture." 16 Oct 2026. https://arxiv.org/abs/2610.23790.

Cite this as:

Weisstein, Eric W. "Lonely Runner Conjecture." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/LonelyRunnerConjecture.html

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