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Erdős problem 1167

Erdős Problem 1167. Let r2r \geq 2 be finite, γ2\gamma \geq 2, and λ\lambda be an infinite cardinal. Let κα\kappa_\alpha be cardinals for all α<γ\alpha < \gamma. Is it true that 2λ(κα+1)α<γr+12^\lambda \to (\kappa_\alpha + 1)_{\alpha < \gamma}^{r+1} implies λ(κα)α<γr?\lambda \to (\kappa_\alpha)_{\alpha < \gamma}^r? Here ++ means cardinal addition, so that κα+1=κα\kappa_\alpha + 1 = \kappa_\alpha if κα\kappa_\alpha is infinite.

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8 retained statements2415f78e850a

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FormalConjectures/ErdosProblems/

1167.lean

Retained formal statement1 of 8

The partition relation μ(ν)1r\mu \to (\nu)^r_1 with a single color is equivalent to νμ\nu \le \mu.

FormalConjectures/ErdosProblems/1167.leanErdos1167.cardinalPartitionRel_one2 linesExact file
∀ (μ : Cardinal.{u}) (r : ℕ) (ν : Ordinal.ToType 1 → Cardinal.{u}),  Combinatorics.cardinalPartitionRel μ r 1 ν ↔ μ ≥ ν Erdos1167.i0
APIStatement only, no proof

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