diff --git a/Nevanlinna/divisor.lean b/Nevanlinna/divisor.lean index aa3c5d4..e498d42 100644 --- a/Nevanlinna/divisor.lean +++ b/Nevanlinna/divisor.lean @@ -23,6 +23,41 @@ instance attribute [coe] Divisor.toFun +theorem Divisor.discreteSupport + {U : Set ℂ} + (hU : IsClosed U) + (D : Divisor U) : + DiscreteTopology D.toFun.support := by + apply discreteTopology_subtype_iff.mpr + intro x hx + apply inf_principal_eq_bot.mpr + by_cases h₁x : x ∈ U + · let A := D.locallyFiniteInU x h₁x + refine mem_nhdsWithin.mpr ?_ + rw [eventuallyEq_nhdsWithin_iff] at A + obtain ⟨U, h₁U, h₂U, h₃U⟩ := eventually_nhds_iff.1 A + use U + constructor + · exact h₂U + · constructor + · exact h₃U + · intro y hy + let C := h₁U y hy.1 hy.2 + tauto + · refine mem_nhdsWithin.mpr ?_ + use Uᶜ + constructor + · simpa + · constructor + · tauto + · intro y _ + let A := D.supportInU + simp at A + simp + exact False.elim (h₁x (A x hx)) + + + theorem Divisor.closedSupport {U : Set ℂ} (hU : IsClosed U)