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Minimum Overlap Problem


The minimum overlap problem asks how evenly the differences between two equal parts of a set of consecutive integers can be distributed (Erdős 1955, White 2023). Partition {1,...,2N} into sets A and B with cardinalities |A|=|B|=N. For an integer k, define

 M_k(A,B)=|{(a,b) in A×B:a-b=k}|.
(1)

The minimum possible largest overlap is

 M(N)=min_(A,B)max_(k in Z)M_k(A,B),
(2)

where the minimum ranges over these set partitions. For example, N=2 admits A={1,4} and B={2,3}, for which every nonzero overlap has size 1, so M(2)=1.

The limiting minimum overlap constant is

 c=lim_(N->infty)(M(N))/N.
(3)

Its exact value is unknown. Haugland (2016) and White (2023) established the respective upper and lower bounds giving

 0.379005<c<0.380927.
(4)

The problem is numbered 36 in the Erdős problems collection (Bloom 2026).

Price (2026) reported the improved lower bound

 c>0.38055470.
(5)

The argument uses an optimization certificate with rigorous interval arithmetic. Price reports assistance from GPT Pro. As of Oct. 5, 2026, VibeMathed had independently reproduced the finite certificate checks, but independent specialist review of the complete reduction to the limiting problem had not been reported (VibeMathed 2026). The computed certificate and the general reduction have different verification scopes.


See also

Erdős Problems

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References

Bloom, T. F. "Erdős Problem 36." Erdős Problems. 2026. https://www.erdosproblems.com/36.Erdős, P. "Some Remarks on Number Theory." Riveon Lematematika 9, 45-48, 1955.Haugland, J. K. "The Minimum Overlap Problem Revisited." 23 Sep 2016. https://arxiv.org/abs/1609.08000.Price, L. "A Certified Lower Bound for Minimum Overlap." 2026. https://github.com/Leeham06972452/erdos-36-lower-bound.VibeMathed. "Lower Bound 0.38055470 for Erdős's Minimum Overlap Constant." Oct. 1, 2026. https://vibemathed.com/problem/lower-bound-0-38055470-for-erdos-s-minimum-overlap-constant.White, E. P. "A New Bound for Erdős' Minimum Overlap Problem." Acta Arith. 208, 235-255, 2023. https://doi.org/10.4064/aa220728-7-6.

Cite this as:

Weisstein, Eric W. "Minimum Overlap Problem." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/MinimumOverlapProblem.html

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