PPL 046 / 177 permanent IDsPrize Problem Ledger · PPLChecked 2026.07.26
Prize Problem LedgerErdősPPL 046Erdős Problem #161

Permanent problem IDPPL 046

Verified openErdősconjecture

Combinatorics

Erdős Problem #161

Let α∈[0,1/2) and n,t≥ 1. Let F^((t))(n,α) be the largest m such that we can 2-colour the edges of the complete t-uniform hypergraph on n vertices such that if X⊆ [n] with | X| ≥ m then there are at least α C(| X|, t) many t-subsets of X of each colour. For fixed n,t as we change α from 0 to 1/2 does F^((t))(n,α) increase continuously or are there jumps? Only one jump?

combinatoricsramsey theorydiscrepancy
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The problem

Let α∈[0,1/2) and n,t≥ 1. Let F^((t))(n,α) be the largest m such that we can 2-colour the edges of the complete t-uniform hypergraph on n vertices such that if X⊆ [n] with | X| ≥ m then there are at least α C(| X|, t) many t-subsets of X of each colour. For fixed n,t as we change α from 0 to 1/2 does F^((t))(n,α) increase continuously or are there jumps? Only one jump?

Open since1990exact
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