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Erdős problem 602

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Does every almost-disjoint family of countably infinite sets whose pairwise intersections all have size ≠ 1 have Property B?

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8 retained statements36c6d0fef71a

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FormalConjectures/ErdosProblems/

602.lean

Retained formal statement8 of 8

Unique index set.

If the index set has exactly one element (i.e., [Unique I]), then Property B holds: any 2-colouring that makes the single set A (default : I) non-monochromatic works. This follows from the single-set case.

FormalConjectures/ErdosProblems/602.leanErdos602.erdos_602.variants.unique_index1 lineExact file
∀ {α : Type u_1} (I : Type u_2) [Unique I] (A : I → Set α), (∀ (i : I), (A i).Infinite) → Erdos602.HasPropertyB I A
TextbookStatement only, no proof