diff --git a/Aristotle/Basic.lean b/Aristotle/Basic.lean
index 41ca742..392694d 100644
--- a/Aristotle/Basic.lean
+++ b/Aristotle/Basic.lean
@@ -1,60 +1,7 @@
-import Mathlib.Analysis.Meromorphic.Basic
-import Mathlib.Analysis.Calculus.Deriv.Mul
-import Mathlib.Analysis.Calculus.Deriv.ZPow
-import Mathlib.Analysis.Calculus.Deriv.Shift
+import Mathlib
 
 open MeromorphicOn Real Set Classical Topology
 
-@[simp]
-theorem eventually_nhdsNE_eventually_nhds_iff_eventually_nhdsNE
-    {α : Type*} [TopologicalSpace α] [T1Space α] {a : α} {p : α → Prop} :
-    (∀ᶠ y in 𝓝[≠] a, ∀ᶠ x in 𝓝 y, p x) ↔ ∀ᶠ x in 𝓝[≠] a, p x := by
-  nth_rw 2 [← eventually_eventually_nhdsWithin]
-  constructor
-  · intro h
-    filter_upwards [h] with _ hy
-    exact eventually_nhdsWithin_of_eventually_nhds hy
-  · intro h
-    filter_upwards [h, eventually_nhdsWithin_of_forall fun _ a ↦ a] with _ _ _
-    simp_all [IsOpen.nhdsWithin_eq]
-
-theorem Filter.EventuallyEq.nhdsNE_deriv
-    {𝕜 : Type u} [NontriviallyNormedField 𝕜]
-    {F : Type v} [NormedAddCommGroup F] [NormedSpace 𝕜 F] {f f₁ : 𝕜 → F} {x : 𝕜}
-    (h : f₁ =ᶠ[𝓝[≠] x] f) :
-    deriv f₁ =ᶠ[𝓝[≠] x] deriv f := by
-  rw [Filter.EventuallyEq, ← eventually_nhdsNE_eventually_nhds_iff_eventually_nhdsNE] at *
-  filter_upwards [h] with y hy
-  apply Filter.EventuallyEq.deriv hy
-
-variable
-  {𝕜 : Type*} [NontriviallyNormedField 𝕜]
-  {E : Type*} [NormedAddCommGroup E] [NormedSpace 𝕜 E] [CompleteSpace E]
-  {U : Set 𝕜} {f g : 𝕜 → E} {a : WithTop E} {a₀ : E}
-
-@[fun_prop]
-theorem AnalyticAt.deriv₁
-    {𝕜 : Type u} [NontriviallyNormedField 𝕜]
-    {F : Type v} [NormedAddCommGroup F] [NormedSpace 𝕜 F] [CompleteSpace F]
-    {f : 𝕜 → F} {x : 𝕜}
-    (h : AnalyticAt 𝕜 f x) :
-    AnalyticAt 𝕜 (deriv f) x := by
-  obtain ⟨r, hr, h⟩ := h.exists_ball_analyticOnNhd
-  exact h.deriv x (by simp [hr])
-
-/-- Derivatives of meromorphic functions are meromorphic. -/
-@[fun_prop]
-theorem meromorphicAt_deriv {f : 𝕜 → E} {x : 𝕜} (h : MeromorphicAt f x) :
-    MeromorphicAt (deriv f) x := by
-  rw [MeromorphicAt.iff_eventuallyEq_zpow_smul_analyticAt] at h
-  obtain ⟨n, g, h₁g, h₂g⟩ := h
-  have : deriv (fun z ↦ (z - x) ^ n • g z)
-      =ᶠ[𝓝[≠] x] fun z ↦ (n * (z - x) ^ (n - 1)) • g z + (z - x) ^ n • deriv g z := by
-    filter_upwards [eventually_nhdsWithin_of_eventually_nhds h₁g.eventually_analyticAt,
-      eventually_nhdsWithin_of_forall fun _ a ↦ a] with z₀ h₁ h₂
-    rw [deriv_smul (DifferentiableAt.zpow (by fun_prop) (by simp_all [sub_ne_zero_of_ne h₂])) (by fun_prop),
-      add_comm, deriv_comp_sub_const (f := (· ^ n))]
-    aesop
-  rw [MeromorphicAt.meromorphicAt_congr (Filter.EventuallyEq.nhdsNE_deriv h₂g),
-    MeromorphicAt.meromorphicAt_congr this]
-  fun_prop
+lemma meromorphic_measurable {f : ℂ → ℂ} (h : MeromorphicOn f ⊤) :
+    Measurable f := by
+  sorry