feat(ErdosProblems): 602 #1357
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feat(ErdosProblems): 602 #1357
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YaelDillies
reviewed
Dec 10, 2025
YaelDillies
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YaelDillies
reviewed
Dec 15, 2025
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| (∃ (c : α → Fin 2), | ||
| ∀ i, #(c '' {x : α | x ∈ A i}) ≠ 1) ↔ answer(sorry) := by |
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What about
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| (∃ (c : α → Fin 2), | |
| ∀ i, #(c '' {x : α | x ∈ A i}) ≠ 1) ↔ answer(sorry) := by | |
| (∃ c : α → Fin 2, ∀ i, (c '' A i).Nontrivial) ↔ answer(sorry) := by |
YaelDillies
reviewed
Dec 15, 2025
| /-- | ||
| **Erdős Problem 602:** | ||
| Let $(A_i)$ be a family of sets with $|A_i| = \aleph_0$ for all $i$, such that for any $i \neq j$ we have | ||
| $|A_i \cap A_j|$ finite and $\neq 1$. |
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You seem to be missing the \ne 1 condition in the lean
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| variable (ι : Type u) (α : Type v) (A : ι → Set α) (h : ∀ i, #(A i) = ℵ₀) | ||
| variable (hij : Pairwise fun i j ↦ (A i ∩ A j).Finite) |
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Can you include all these variables in the ↔ answer(sorry)? To spare you some trouble, let's make the statement universe monomorphic
Suggested change
| variable (ι : Type u) (α : Type v) (A : ι → Set α) (h : ∀ i, #(A i) = ℵ₀) | |
| variable (hij : Pairwise fun i j ↦ (A i ∩ A j).Finite) | |
| variable (ι α : Type) (A : ι → Set α) (h : ∀ i, #(A i) = ℵ₀) | |
| variable (hij : Pairwise fun i j ↦ (A i ∩ A j).Finite) |
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fixes #821