Erdős, Ko and Rado: intersecting families of finite sets

What changed

Proved the maximum size of a pairwise-intersecting uniform family under the stated ground-set condition.

Scientific scope

The record is the exact three-author 1961 Quarterly Journal of Mathematics paper. Its uniformity and size hypotheses matter; later Hilton-Milner, t-intersection, stability and probabilistic extensions remain separate.

Evidence

The linked sources identify this contribution and its scope. WRS has not independently reconstructed the scientific claims. The record is the exact three-author 1961 Quarterly Journal of Mathematics paper. Its uniformity and size hypotheses matter; later Hilton-Milner, t-intersection, stability and probabilistic extensions remain separate.

Contributors

• P. Erdős · SCIENCE: Named source author of the scoped work; individual effort shares are not measured.
• Chao Ko · SCIENCE: Named source author of the scoped work; individual effort shares are not measured.
• R. Rado · SCIENCE: Named source author of the scoped work; individual effort shares are not measured.

• Oxford Academic page for the Erdős-Ko-Rado paper
• Erdős archive copy of the intersecting-families paper

Provisional WRS assessment, edition 2026-10-16.1. Independent expert calibration is pending. This grade does not certify correctness or assign ownership.

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