-- Mathlib/NumberTheory/Rayleigh.lean
theorem compl_beattySeq {r s : ℝ} (hrs : r.IsConjExponent s) :
    {beattySeq r k | k}ᶜ = {beattySeq' s k | k}

Proof state:
case pos
r s : ℝ
hrs : r.IsConjExponent s
j : ℤ
h₁ : j ∉ {x | ∃ k, beattySeq r k = x}
h₂ : j ∈ {x | ∃ k, beattySeq' s k = x}
⊢ j ∈ {x | ∃ k, beattySeq r k = x}ᶜ ↔ j ∈ {x | ∃ k, beattySeq' s k = x}

Tactic:
simp only [Set.mem_compl_iff, h₁, h₂, not_false_eq_true]

Result:
no goals

Proof state:
case pos
r s : ℝ
hrs : r.IsConjExponent s
j : ℤ
h₁ : j ∈ {x | ∃ k, beattySeq r k = x}
h₂ : j ∈ {x | ∃ k, beattySeq' s k = x}
⊢ j ∈ {x | ∃ k, beattySeq r k = x}ᶜ ↔ j ∈ {x | ∃ k, beattySeq' s k = x}

Tactic:
exact (Set.not_disjoint_iff.2 ⟨j, h₁, h₂⟩ (Beatty.no_collision hrs)).elim

Result:
no goals

Proof state:
r s : ℝ
hrs : r.IsConjExponent s
⊢ {x | ∃ k, beattySeq r k = x}ᶜ = {x | ∃ k, beattySeq' s k = x}

Tactic:
ext j

Result:
case h
r s : ℝ
hrs : r.IsConjExponent s
j : ℤ
⊢ j ∈ {x | ∃ k, beattySeq r k = x}ᶜ ↔ j ∈ {x | ∃ k, beattySeq' s k = x}

Proof state:
case h
r s : ℝ
hrs : r.IsConjExponent s
j : ℤ
⊢ j ∈ {x | ∃ k, beattySeq r k = x}ᶜ ↔ j ∈ {x | ∃ k, beattySeq' s k = x}

Tactic:
by_cases h₁ : j ∈ {beattySeq r k | k} <;> by_cases h₂ : j ∈ {beattySeq' s k | k}

Result:
case pos
r s : ℝ
hrs : r.IsConjExponent s
j : ℤ
h₁ : j ∈ {x | ∃ k, beattySeq r k = x}
h₂ : j ∈ {x | ∃ k, beattySeq' s k = x}
⊢ j ∈ {x | ∃ k, beattySeq r k = x}ᶜ ↔ j ∈ {x | ∃ k, beattySeq' s k = x}

case neg
r s : ℝ
hrs : r.IsConjExponent s
j : ℤ
h₁ : j ∈ {x | ∃ k, beattySeq r k = x}
h₂ : j ∉ {x | ∃ k, beattySeq' s k = x}
⊢ j ∈ {x | ∃ k, beattySeq r k = x}ᶜ ↔ j ∈ {x | ∃ k, beattySeq' s k = x}

case pos
r s : ℝ
hrs : r.IsConjExponent s
j : ℤ
h₁ : j ∉ {x | ∃ k, beattySeq r k = x}
h₂ : j ∈ {x | ∃ k, beattySeq' s k = x}
⊢ j ∈ {x | ∃ k, beattySeq r k = x}ᶜ ↔ j ∈ {x | ∃ k, beattySeq' s k = x}

case neg
r s : ℝ
hrs : r.IsConjExponent s
j : ℤ
h₁ : j ∉ {x | ∃ k, beattySeq r k = x}
h₂ : j ∉ {x | ∃ k, beattySeq' s k = x}
⊢ j ∈ {x | ∃ k, beattySeq r k = x}ᶜ ↔ j ∈ {x | ∃ k, beattySeq' s k = x}

Proof state:
case neg
r s : ℝ
hrs : r.IsConjExponent s
j : ℤ
h₁ : j ∉ {x | ∃ k, beattySeq r k = x}
h₂ : j ∉ {x | ∃ k, beattySeq' s k = x}
k : ℤ
h₁₁ : ↑k < ↑j / r
h₁₂ : (↑j + 1) / r ≤ ↑k + 1
m : ℤ
h₂₁ : ↑m ≤ ↑j / s
h₂₂ : (↑j + 1) / s < ↑m + 1
⊢ j ∈ {x | ∃ k, beattySeq r k = x}ᶜ ↔ j ∈ {x | ∃ k, beattySeq' s k = x}

Tactic:
exact (Beatty.no_anticollision hrs ⟨j, k, m, h₁₁, h₁₂, h₂₁, h₂₂⟩).elim

Result:
no goals

Proof state:
case neg
r s : ℝ
hrs : r.IsConjExponent s
j : ℤ
h₁ : j ∉ {x | ∃ k, beattySeq r k = x}
h₂ : j ∉ {x | ∃ k, beattySeq' s k = x}
k : ℤ
h₁₁ : ↑k < ↑j / r
h₁₂ : (↑j + 1) / r ≤ ↑k + 1
⊢ j ∈ {x | ∃ k, beattySeq r k = x}ᶜ ↔ j ∈ {x | ∃ k, beattySeq' s k = x}

Tactic:
have ⟨m, h₂₁, h₂₂⟩ := (Beatty.hit_or_miss' hrs.symm.pos).resolve_left h₂

Result:
case neg
r s : ℝ
hrs : r.IsConjExponent s
j : ℤ
h₁ : j ∉ {x | ∃ k, beattySeq r k = x}
h₂ : j ∉ {x | ∃ k, beattySeq' s k = x}
k : ℤ
h₁₁ : ↑k < ↑j / r
h₁₂ : (↑j + 1) / r ≤ ↑k + 1
m : ℤ
h₂₁ : ↑m ≤ ↑j / s
h₂₂ : (↑j + 1) / s < ↑m + 1
⊢ j ∈ {x | ∃ k, beattySeq r k = x}ᶜ ↔ j ∈ {x | ∃ k, beattySeq' s k = x}

Proof state:
case neg
r s : ℝ
hrs : r.IsConjExponent s
j : ℤ
h₁ : j ∉ {x | ∃ k, beattySeq r k = x}
h₂ : j ∉ {x | ∃ k, beattySeq' s k = x}
⊢ j ∈ {x | ∃ k, beattySeq r k = x}ᶜ ↔ j ∈ {x | ∃ k, beattySeq' s k = x}

Tactic:
have ⟨k, h₁₁, h₁₂⟩ := (Beatty.hit_or_miss hrs.pos).resolve_left h₁

Result:
case neg
r s : ℝ
hrs : r.IsConjExponent s
j : ℤ
h₁ : j ∉ {x | ∃ k, beattySeq r k = x}
h₂ : j ∉ {x | ∃ k, beattySeq' s k = x}
k : ℤ
h₁₁ : ↑k < ↑j / r
h₁₂ : (↑j + 1) / r ≤ ↑k + 1
⊢ j ∈ {x | ∃ k, beattySeq r k = x}ᶜ ↔ j ∈ {x | ∃ k, beattySeq' s k = x}

Proof state:
case neg
r s : ℝ
hrs : r.IsConjExponent s
j : ℤ
h₁ : j ∈ {x | ∃ k, beattySeq r k = x}
h₂ : j ∉ {x | ∃ k, beattySeq' s k = x}
⊢ j ∈ {x | ∃ k, beattySeq r k = x}ᶜ ↔ j ∈ {x | ∃ k, beattySeq' s k = x}

Tactic:
simp only [Set.mem_compl_iff, h₁, h₂, not_true_eq_false]

Result:
no goals