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Erdos Conjecture 386 #1239
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Erdos Conjecture 386 #1239
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callesonne
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Thanks for the contribution! Here are some comments :)
| def erdos_386_equation (a b : ℕ) (A : Finset ℕ) := | ||
| Nat.choose a b = ∏ α ∈ A, α | ||
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| /- |
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| /- | |
| /-- |
Docstrings (i.e. comments over theorems / definitions) must start like this.
| def erdos_386_equation (a b : ℕ) (A : Finset ℕ) := | ||
| Nat.choose a b = ∏ α ∈ A, α |
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Since this is only used once in the statement of erdos_386 I would not add it as a definition, and rather just state it there.
| The following set contains all solutions `(n, k, P)` to the Erdős problem 386. | ||
| A solution is a tuple `(n, k, P)`, where `n ≥ 2` and `k` are an integers and `P` | ||
| is a non-empty finite set of | ||
| distinct prime numbers, such that it's product is binomial coefficient n choose k. |
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Could you make this comment more precise? For example you do not mention that 2 ≤ k ≤ n - 2 and that the elements of P need to be primes.
| def erdos_386_solutions : Set (ℕ × ℕ × Finset ℕ) := { | ||
| (n, k, P) | | ||
| (n ≥ 2 ∧ 2 ≤ k ∧ k ≤ n - 2) ∧ | ||
| P.Nonempty ∧ | ||
| (∀ p ∈ P, p.Prime) ∧ | ||
| erdos_386_equation n k P | ||
| } |
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I think this is missing the condition that the primes are consecutive.
| -/ | ||
| def erdos_386_solutions : Set (ℕ × ℕ × Finset ℕ) := { | ||
| (n, k, P) | | ||
| (n ≥ 2 ∧ 2 ≤ k ∧ k ≤ n - 2) ∧ |
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| (n ≥ 2 ∧ 2 ≤ k ∧ k ≤ n - 2) ∧ | |
| (n ≥ 2 ∧ 2 ≤ k ∧ k ≤ n - 2) ∧ |
I would put either n ≥ 4 or no condition on n here, since for n < 3 no such k exist.
This is the statement of Erdős Conjecture 386.
fixes #703