FormalConjectures/ErdosProblems/868.lean

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L4DEL
Lean4 Domain Explanation Language

Credit: The upstream authors and contributors retain credit for the project and mathematics. lean4-explainer only renders their pinned source and adds the separately disclosed explanation layer.

Project sources: Pinned project documentation, Formal Conjectures paper, arXiv v1

5 declarations, 4 contain sorry, 0 declared as axioms

Erdős Problem 868

References:

Imports (1)
  1. def Erdos868.ncard_add_repr line 40 source

    standard axioms: Classical.choice, Quot.sound, propext what this means

    Statement uses: Set, Nat

    Proof uses: Set.ncard, Fin, Set.ofPred, And, Monotone, LE.le, Set.range, Eq, Finset.sum, Finset.univ

    6 instances, coercions and auxiliary constants left out.

  2. theorem Erdos868.erdos_868.parts.i Let $A$ be an additive basis of order $2$, let $f(n)$ denote the number of ways in which $n$ can be written as the sum of two elements from $A$ sorry line 50 source

    Source documentation

    Let $A$ be an additive basis of order $2$, let $f(n)$ denote the number of ways in which $n$ can be written as the sum of two elements from $A$. If $f(n) \to \infty$ as $n \to \infty$, then must $A$ contain a minimal additive basis of order $2$?

    Larsen and Larsen [LaLa26] answered this in the negative.

    depends on sorry what this means

    Statement uses: Iff, False, Set, Nat, Set.IsAsymptoticAddBasisOfOrder, OfNat.ofNat, Filter.Tendsto, Erdos868.ncard_add_repr, Filter.atTop, Exists, And, LE.le, Membership.mem, Not, SDiff.sdiff, Singleton.singleton

    Proof uses: sorryAx, Lean.Name, Bool.false, Lean.Name.num, Lean.Name.str, Lean.Name.anonymous

    14 instances, coercions and auxiliary constants left out.

    Tactic trace: 1 steps

    Open to load the checked before-and-after goal states.

    theorem erdos_868.parts.i :
        answer(False) ↔ ∀ (A : Set ℕ), A.IsAsymptoticAddBasisOfOrder 2 →
          atTop.Tendsto (fun n => ncard_add_repr A 2 n) atTop → ∃ B ⊆ A,
          B.IsAsymptoticAddBasisOfOrder 2 ∧ ∀ b ∈ B, ¬(B \ {b}).IsAsymptoticAddBasisOfOrder 2 := by
    …

    Mentions: Erdos868.ncard_add_repr

  3. theorem Erdos868.erdos_868.parts.ii Let $A$ be an additive basis of order $2$, let $f(n)$ denote the number of ways in which $n$ can be written as the sum of two elements from $A$ sorry line 64 source

    Source documentation

    Let $A$ be an additive basis of order $2$, let $f(n)$ denote the number of ways in which $n$ can be written as the sum of two elements from $A$. If $f(n) > \epsilon \log n$ for large $n$ and an arbitrary fixed $\epsilon > 0$, then must $A$ contain a minimal additive basis of order $2$?

    Larsen and Larsen [LaLa26] constructed a counterexample with $f(n) > c \log n$ for all large $n$.

    depends on sorry what this means

    Statement uses: Iff, False, Set, Nat, Real, GT.gt, OfNat.ofNat, Set.IsAsymptoticAddBasisOfOrder, Filter.Eventually, LT.lt, HMul.hMul, Real.log, Erdos868.ncard_add_repr, Filter.atTop, Exists, And, LE.le, Membership.mem, Not, SDiff.sdiff and 1 more

    Proof uses: sorryAx, Lean.Name, Bool.false, Lean.Name.num, Lean.Name.str, Lean.Name.anonymous

    28 instances, coercions and auxiliary constants left out.

    Tactic trace: 1 steps

    Open to load the checked before-and-after goal states.

    theorem erdos_868.parts.ii :
        answer(False) ↔ ∀ᵉ (A : Set ℕ) (ε > 0), A.IsAsymptoticAddBasisOfOrder 2 →
          (∀ᶠ (n : ℕ) in atTop, ε * Real.log n < ncard_add_repr A 2 n) → ∃ B ⊆ A,
          B.IsAsymptoticAddBasisOfOrder 2 ∧ ∀ b ∈ B, ¬(B \ {b}).IsAsymptoticAddBasisOfOrder 2 := by
    …

    Mentions: Erdos868.ncard_add_repr

  4. theorem Erdos868.erdos_868.variants.fixed_ε Erdős and Nathanson proved that this is true if $f(n) > c \log n$ for all large $n$, for some fixed constant $c > (\log \frac{4}{3})^{-1}$ sorry line 73 source

    Source documentation

    Erdős and Nathanson proved that this is true if $f(n) > c \log n$ for all large $n$, for some fixed constant $c > (\log \frac{4}{3})^{-1}$.

    depends on sorry what this means

    Statement uses: Iff, True, Set, Nat, Real, GT.gt, Inv.inv, Real.log, HDiv.hDiv, OfNat.ofNat, Set.IsAsymptoticAddBasisOfOrder, Filter.Eventually, LT.lt, HMul.hMul, Erdos868.ncard_add_repr, Filter.atTop, Exists, And, LE.le, Membership.mem and 3 more

    Proof uses: sorryAx, Lean.Name, Bool.false, Lean.Name.num, Lean.Name.str, Lean.Name.anonymous

    38 instances, coercions and auxiliary constants left out.

    Tactic trace: 1 steps

    Open to load the checked before-and-after goal states.

    theorem erdos_868.variants.fixed_ε :
        answer(True) ↔ ∀ᵉ (A : Set ℕ) (c > (Real.log (4 / 3))⁻¹), A.IsAsymptoticAddBasisOfOrder 2 →
          (∀ᶠ (n : ℕ) in atTop, c * Real.log n < ncard_add_repr A 2 n) → ∃ B ⊆ A,
          B.IsAsymptoticAddBasisOfOrder 2 ∧ ∀ b ∈ B, ¬(B \ {b}).IsAsymptoticAddBasisOfOrder 2 := by
    …

    Mentions: c, Erdos868.ncard_add_repr

  5. theorem Erdos868.erdos_868.variants.Hartter_Nathanson sorry line 84 source

    depends on sorry what this means

    Statement uses: Nat, LT.lt, OfNat.ofNat, Exists, Set, And, Set.IsAsymptoticAddBasisOfOrder, LE.le, Membership.mem, SDiff.sdiff, Singleton.singleton

    Proof uses: sorryAx, Lean.Name, Bool.false, Lean.Name.num, Lean.Name.str, Lean.Name.anonymous

    14 instances, coercions and auxiliary constants left out.

    Tactic trace: 1 steps

    Open to load the checked before-and-after goal states.