diff --git a/Nevanlinna/holomorphic_zero.lean b/Nevanlinna/holomorphic_zero.lean index 7d8b1a3..d03bb2d 100644 --- a/Nevanlinna/holomorphic_zero.lean +++ b/Nevanlinna/holomorphic_zero.lean @@ -50,13 +50,43 @@ lemma natural_if_toNatNeZero {n : ℕ∞} : n.toNat ≠ 0 → ∃ m : ℕ, m = n contrapose; simp; tauto -theorem zeroDivisor_in_zeroSet +theorem zeroDivisor_localDescription {f : ℂ → ℂ} - {z : ℂ} - (h : z ∈ Function.support (zeroDivisor f)) : - f z = 0 := by + {z₀ : ℂ} + (h : z₀ ∈ Function.support (zeroDivisor f)) : + ∃ (g : ℂ → ℂ), AnalyticAt ℂ g z₀ ∧ g z₀ ≠ 0 ∧ ∀ᶠ (z : ℂ) in nhds z₀, f z = (z - z₀) ^ (zeroDivisor f z₀) • g z := by + + have A : zeroDivisor f ↑z₀ ≠ 0 := by exact h + let B := zeroDivisor_eq_ord_AtZeroDivisorSupport h + rw [B] at A + have C := natural_if_toNatNeZero A + obtain ⟨m, hm⟩ := C + have h₂m : m ≠ 0 := by + rw [← hm] at A + simp at A + assumption + rw [eq_comm] at hm + let E := AnalyticAt.order_eq_nat_iff (analyticAtZeroDivisorSupport h) m + let F := hm + rw [E] at F + + have : m = zeroDivisor f z₀ := by + rw [B, hm] + simp + rwa [this] at F + + +theorem zeroDivisor_zeroSet + {f : ℂ → ℂ} + {z₀ : ℂ} + (h : z₀ ∈ Function.support (zeroDivisor f)) : + f z₀ = 0 := by + obtain ⟨g, _, _, h₃⟩ := zeroDivisor_localDescription h + rw [Filter.Eventually.self_of_nhds h₃] + simp + left + exact h - sorry theorem discreteZeros {f : ℂ → ℂ} : @@ -121,7 +151,7 @@ theorem discreteZeros _ ≤ ε₁ := by exact min_le_left ε₁ ε₂ let F := h₂ε₂ y.1 h₂y - rw [zeroDivisor_in_zeroSet y.2] at F + rw [zeroDivisor_zeroSet y.2] at F simp at F simp [h₂m] at F @@ -145,7 +175,22 @@ theorem eliminatingZeros {f : ℂ → ℂ} {z₀ : ℂ} {R : ℝ} - (h₁f : ∀ z ∈ Metric.ball z₀ R, HolomorphicAt f z) + (h₁f : ∀ z ∈ Metric.closedBall z₀ R, HolomorphicAt f z) (h₂f : ∃ z ∈ Metric.ball z₀ R, f z ≠ 0) : ∃ F : ℂ → ℂ, ∀ z ∈ Metric.ball z₀ R, (HolomorphicAt F z) ∧ (f z = (F z) * ∏ᶠ a ∈ Metric.ball z₀ R, (z - a) ^ (zeroDivisor f a) ) := by - sorry + + let F : ℂ → ℂ := by + intro z + if hz : z ∈ (Metric.closedBall z₀ R) ∩ Function.support (zeroDivisor f) then + exact 0 + else + exact f z * (∏ᶠ a ∈ Metric.ball z₀ R, (z - a) ^ (zeroDivisor f a))⁻¹ + + use F + intro z hz + by_cases h₂z : z ∈ (Metric.closedBall z₀ R) ∩ Function.support (zeroDivisor f) + · -- Positive case + sorry + + · -- Negative case + sorry