-- Mathlib/Algebra/Module/ZLattice/Covolume.lean
theorem tendsto_card_le_div'' [FiniteDimensional ℝ E] [MeasurableSpace E] [BorelSpace E]
    [Nonempty ι] {X : Set E} (hX : ∀ ⦃x⦄ ⦃r : ℝ⦄, x ∈ X → 0 < r → r • x ∈ X)
    {F : E → ℝ} (h₁ : ∀ x ⦃r : ℝ⦄, 0 ≤ r →  F (r • x) = r ^ card ι * (F x))
    (h₂ : IsBounded {x ∈ X | F x ≤ 1}) (h₃ : MeasurableSet {x ∈ X | F x ≤ 1})
    (h₄ : volume (frontier ((b.ofZLatticeBasis ℝ L).equivFun '' {x | x ∈ X ∧ F x ≤ 1})) = 0) :
    Tendsto (fun c : ℝ ↦
      Nat.card ({x ∈ X | F x ≤ c} ∩ L : Set E) / (c : ℝ))
        atTop (𝓝 (volume ((b.ofZLatticeBasis ℝ).equivFun '' {x ∈ X | F x ≤ 1})).toReal)

Proof state:
case refine_1
E : Type u_1
inst✝⁸ : NormedAddCommGroup E
inst✝⁷ : NormedSpace ℝ E
L : Submodule ℤ E
inst✝⁶ : DiscreteTopology ↥L
inst✝⁵ : IsZLattice ℝ L
ι : Type u_2
inst✝⁴ : Fintype ι
b : Basis ι ℤ ↥L
inst✝³ : FiniteDimensional ℝ E
inst✝² : MeasurableSpace E
inst✝¹ : BorelSpace E
inst✝ : Nonempty ι
X : Set E
hX : ∀ ⦃x : E⦄ ⦃r : ℝ⦄, x ∈ X → 0 < r → r • x ∈ X
F : E → ℝ
h₁ : ∀ (x : E) ⦃r : ℝ⦄, 0 ≤ r → F (r • x) = r ^ card ι * F x
h₂ : Bornology.IsBounded {x | x ∈ X ∧ F x ≤ 1}
h₃ : MeasurableSet {x | x ∈ X ∧ F x ≤ 1}
h₄ : volume (frontier (⇑(Basis.ofZLatticeBasis ℝ L b).equivFun '' {x | x ∈ X ∧ F x ≤ 1})) = 0
⊢ ((fun x =>
        ↑(Nat.card
              ↑(⇑(Basis.ofZLatticeBasis ℝ L b).equivFun '' {x | x ∈ X ∧ F x ≤ 1} ∩
                  x⁻¹ • ↑(span ℤ (Set.range ⇑(Pi.basisFun ℝ ι))))) /
          x ^ card ι) ∘
      fun x => x ^ (↑(card ι))⁻¹) =ᶠ[atTop]
    fun c => ↑(Nat.card ↑({x | x ∈ X ∧ F x ≤ c} ∩ ↑L)) / c

Tactic:
filter_upwards [eventually_gt_atTop 0] with c hc

Result:
case h
E : Type u_1
inst✝⁸ : NormedAddCommGroup E
inst✝⁷ : NormedSpace ℝ E
L : Submodule ℤ E
inst✝⁶ : DiscreteTopology ↥L
inst✝⁵ : IsZLattice ℝ L
ι : Type u_2
inst✝⁴ : Fintype ι
b : Basis ι ℤ ↥L
inst✝³ : FiniteDimensional ℝ E
inst✝² : MeasurableSpace E
inst✝¹ : BorelSpace E
inst✝ : Nonempty ι
X : Set E
hX : ∀ ⦃x : E⦄ ⦃r : ℝ⦄, x ∈ X → 0 < r → r • x ∈ X
F : E → ℝ
h₁ : ∀ (x : E) ⦃r : ℝ⦄, 0 ≤ r → F (r • x) = r ^ card ι * F x
h₂ : Bornology.IsBounded {x | x ∈ X ∧ F x ≤ 1}
h₃ : MeasurableSet {x | x ∈ X ∧ F x ≤ 1}
h₄ : volume (frontier (⇑(Basis.ofZLatticeBasis ℝ L b).equivFun '' {x | x ∈ X ∧ F x ≤ 1})) = 0
c : ℝ
hc : 0 < c
⊢ ((fun x =>
          ↑(Nat.card
                ↑(⇑(Basis.ofZLatticeBasis ℝ L b).equivFun '' {x | x ∈ X ∧ F x ≤ 1} ∩
                    x⁻¹ • ↑(span ℤ (Set.range ⇑(Pi.basisFun ℝ ι))))) /
            x ^ card ι) ∘
        fun x => x ^ (↑(card ι))⁻¹)
      c =
    ↑(Nat.card ↑({x | x ∈ X ∧ F x ≤ c} ∩ ↑L)) / c

Proof state:
case h.intro.e_a.e_a
E : Type u_1
inst✝⁸ : NormedAddCommGroup E
inst✝⁷ : NormedSpace ℝ E
L : Submodule ℤ E
inst✝⁶ : DiscreteTopology ↥L
inst✝⁵ : IsZLattice ℝ L
ι : Type u_2
inst✝⁴ : Fintype ι
b : Basis ι ℤ ↥L
inst✝³ : FiniteDimensional ℝ E
inst✝² : MeasurableSpace E
inst✝¹ : BorelSpace E
inst✝ : Nonempty ι
X : Set E
hX : ∀ ⦃x : E⦄ ⦃r : ℝ⦄, x ∈ X → 0 < r → r • x ∈ X
F : E → ℝ
h₁ : ∀ (x : E) ⦃r : ℝ⦄, 0 ≤ r → F (r • x) = r ^ card ι * F x
h₂ : Bornology.IsBounded {x | x ∈ X ∧ F x ≤ 1}
h₃ : MeasurableSet {x | x ∈ X ∧ F x ≤ 1}
h₄ : volume (frontier (⇑(Basis.ofZLatticeBasis ℝ L b).equivFun '' {x | x ∈ X ∧ F x ≤ 1})) = 0
c : ℝ
hc : 0 < c
aux₁ : ↑(card ι) ≠ 0
aux₂ : 0 < c ^ (↑(card ι))⁻¹
aux₃ : (c ^ (↑(card ι))⁻¹)⁻¹ ≠ 0
aux₄ : c ^ (-(↑(card ι))⁻¹) ≠ 0
hc₁ : 0 ≤ c
hc₂ : 0 ≠ c
x✝ : E
⊢ x✝ ∈ {x | x ∈ X ∧ F x ≤ c} ∧ x✝ ∈ ↑L ↔
    (Basis.ofZLatticeBasis ℝ L b).equivFun x✝ ∈ ⇑(Basis.ofZLatticeBasis ℝ L b).equivFun '' {x | x ∈ X ∧ F x ≤ c} ∧
      (Basis.ofZLatticeBasis ℝ L b).equivFun x✝ ∈ ↑(span ℤ (Set.range ⇑(Pi.basisFun ℝ ι)))

Tactic:
simp_rw [SetLike.mem_coe, Set.mem_image, EmbeddingLike.apply_eq_iff_eq, exists_eq_right,
  and_congr_right_iff, ← b.ofZLatticeBasis_span ℝ, Basis.mem_span_iff_repr_mem,
  Pi.basisFun_repr, Basis.equivFun_apply, implies_true]

Result:
no goals