PPL 077 / 177 permanent IDsPrize Problem Ledger · PPLChecked 2026.07.26
Prize Problem LedgerErdősPPL 077Erdős Problem #712

Permanent problem IDPPL 077

Verified openErdősconjecture

Graph theory

Erdős Problem #712

Determine, for any k>r>2, the value of (ex_r(n,K_k^r)/C(n, r)), where ex_r(n,K_k^r) is the largest number of r-edges which can placed on n vertices so that there exists no set of k vertices which is covered by all C(k, r) possible r-edges.

graph theoryturan numberhypergraphs
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The problem

Determine, for any k>r>2, the value of (ex_r(n,K_k^r)/C(n, r)), where ex_r(n,K_k^r) is the largest number of r-edges which can placed on n vertices so that there exists no set of k vertices which is covered by all C(k, r) possible r-edges.

Open since1971earliest source
Last checked2026.07.26Catalog verification
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Reward offers

Offer 01$500Paul Erdős / Combinatorics Foundation
Documented

A solution must appear in a reputable journal, with documentation that Erdős offered the displayed amount. Claims are administered by the Combinatorics Foundation; erdosproblems.com does not pay awards.

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Sources & reading