-- Mathlib/Algebra/Module/ZLattice/Basic.lean
theorem ZLattice.rank [hs : IsZLattice K L] : finrank ℤ L = finrank K E

Proof state:
case refine_2
K : Type u_1
inst✝⁷ : NormedLinearOrderedField K
inst✝⁶ : HasSolidNorm K
inst✝⁵ : FloorRing K
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : NormedSpace K E
inst✝² : FiniteDimensional K E
inst✝¹ : ProperSpace E
L : Submodule ℤ E
inst✝ : DiscreteTopology ↥L
hs : IsZLattice K L
this✝³ : Module.Finite ℤ ↥L
this✝² : Free ℤ ↥L
this✝¹ : Module ℚ E
b₀ : Basis (Free.ChooseBasisIndex ℤ ↥L) ℤ ↥L := Free.chooseBasis ℤ ↥L
b : Free.ChooseBasisIndex ℤ ↥L → E := Subtype.val ∘ ⇑b₀
this✝ : LinearIndependent ℤ b
h_spanL : span ℤ (Set.range b) = L
h_spanE : span K (Set.range b) = ⊤
h_card : Fintype.card (Free.ChooseBasisIndex ℤ ↥L) = (Set.range b).toFinset.card
t : Set E
ht_inc : t ⊆ Set.range b
ht_span : span K t = span K (Set.range b)
ht_lin : LinearIndependent K Subtype.val
e : Basis (↑t) K E := Basis.mk ht_lin ⋯
this : Fintype ↑t
h : finrank K E < Fintype.card (Free.ChooseBasisIndex ℤ ↥L)
v : E
hv : v ∈ Set.range b \ Set.range ⇑e
a✝ : LinearIndepOn ℚ id (Set.range ⇑e)
x✝ : ℤ
⊢ ↑(floor e (x✝ • v)) ∈ span ℤ (Set.range b)

Tactic:
exact span_mono (by simp [e, ht_inc]) (coe_mem _)

Result:
no goals

Proof state:
case refine_2
K : Type u_1
inst✝⁷ : NormedLinearOrderedField K
inst✝⁶ : HasSolidNorm K
inst✝⁵ : FloorRing K
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : NormedSpace K E
inst✝² : FiniteDimensional K E
inst✝¹ : ProperSpace E
L : Submodule ℤ E
inst✝ : DiscreteTopology ↥L
hs : IsZLattice K L
this✝² : Module.Finite ℤ ↥L
this✝¹ : Free ℤ ↥L
this✝ : Module ℚ E
b₀ : Basis (Free.ChooseBasisIndex ℤ ↥L) ℤ ↥L := Free.chooseBasis ℤ ↥L
b : Free.ChooseBasisIndex ℤ ↥L → E := Subtype.val ∘ ⇑b₀
this : LinearIndependent ℤ b
h_spanL : span ℤ (Set.range b) = L
h_spanE : span K (Set.range b) = ⊤
h_card : Fintype.card (Free.ChooseBasisIndex ℤ ↥L) = (Set.range b).toFinset.card
⊢ finrank K ↥(span K (Set.range b)) ≤ Fintype.card (Free.ChooseBasisIndex ℤ ↥L)

Tactic:
convert finrank_span_le_card (R := K) (Set.range b)

Result:
no goals

Proof state:
K : Type u_1
inst✝⁷ : NormedLinearOrderedField K
inst✝⁶ : HasSolidNorm K
inst✝⁵ : FloorRing K
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : NormedSpace K E
inst✝² : FiniteDimensional K E
inst✝¹ : ProperSpace E
L : Submodule ℤ E
inst✝ : DiscreteTopology ↥L
hs : IsZLattice K L
this✝³ : Module.Finite ℤ ↥L
this✝² : Free ℤ ↥L
this✝¹ : Module ℚ E
b₀ : Basis (Free.ChooseBasisIndex ℤ ↥L) ℤ ↥L := Free.chooseBasis ℤ ↥L
b : Free.ChooseBasisIndex ℤ ↥L → E := Subtype.val ∘ ⇑b₀
this✝ : LinearIndependent ℤ b
h_spanL : span ℤ (Set.range b) = L
h_spanE : span K (Set.range b) = ⊤
h_card : Fintype.card (Free.ChooseBasisIndex ℤ ↥L) = (Set.range b).toFinset.card
t : Set E
ht_inc : t ⊆ Set.range b
ht_span : span K t = span K (Set.range b)
ht_lin : LinearIndependent K Subtype.val
e : Basis (↑t) K E := Basis.mk ht_lin ⋯
this : Fintype ↑t
h : ¬(Set.range b \ t).toFinset.Nonempty
⊢ ¬finrank K E < Fintype.card (Free.ChooseBasisIndex ℤ ↥L)

Tactic:
rw [Finset.not_nonempty_iff_eq_empty, Set.toFinset_diff,
  Finset.sdiff_eq_empty_iff_subset] at h

Result:
K : Type u_1
inst✝⁷ : NormedLinearOrderedField K
inst✝⁶ : HasSolidNorm K
inst✝⁵ : FloorRing K
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : NormedSpace K E
inst✝² : FiniteDimensional K E
inst✝¹ : ProperSpace E
L : Submodule ℤ E
inst✝ : DiscreteTopology ↥L
hs : IsZLattice K L
this✝³ : Module.Finite ℤ ↥L
this✝² : Free ℤ ↥L
this✝¹ : Module ℚ E
b₀ : Basis (Free.ChooseBasisIndex ℤ ↥L) ℤ ↥L := Free.chooseBasis ℤ ↥L
b : Free.ChooseBasisIndex ℤ ↥L → E := Subtype.val ∘ ⇑b₀
this✝ : LinearIndependent ℤ b
h_spanL : span ℤ (Set.range b) = L
h_spanE : span K (Set.range b) = ⊤
h_card : Fintype.card (Free.ChooseBasisIndex ℤ ↥L) = (Set.range b).toFinset.card
t : Set E
ht_inc : t ⊆ Set.range b
ht_span : span K t = span K (Set.range b)
ht_lin : LinearIndependent K Subtype.val
e : Basis (↑t) K E := Basis.mk ht_lin ⋯
this : Fintype ↑t
h : (Set.range b).toFinset ⊆ t.toFinset
⊢ ¬finrank K E < Fintype.card (Free.ChooseBasisIndex ℤ ↥L)

Proof state:
case h.e'_2
K : Type u_1
inst✝⁷ : NormedLinearOrderedField K
inst✝⁶ : HasSolidNorm K
inst✝⁵ : FloorRing K
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : NormedSpace K E
inst✝² : FiniteDimensional K E
inst✝¹ : ProperSpace E
L : Submodule ℤ E
inst✝ : DiscreteTopology ↥L
hs : IsZLattice K L
this✝² : Module.Finite ℤ ↥L
this✝¹ : Free ℤ ↥L
this✝ : Module ℚ E
b₀ : Basis (Free.ChooseBasisIndex ℤ ↥L) ℤ ↥L := Free.chooseBasis ℤ ↥L
b : Free.ChooseBasisIndex ℤ ↥L → E := Subtype.val ∘ ⇑b₀
this : LinearIndependent ℤ b
⊢ span ℤ (Set.range b) = Submodule.map L.subtype (span ℤ (Set.range ⇑b₀))

Tactic:
rw [map_span, Set.range_comp]

Result:
case h.e'_2
K : Type u_1
inst✝⁷ : NormedLinearOrderedField K
inst✝⁶ : HasSolidNorm K
inst✝⁵ : FloorRing K
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : NormedSpace K E
inst✝² : FiniteDimensional K E
inst✝¹ : ProperSpace E
L : Submodule ℤ E
inst✝ : DiscreteTopology ↥L
hs : IsZLattice K L
this✝² : Module.Finite ℤ ↥L
this✝¹ : Free ℤ ↥L
this✝ : Module ℚ E
b₀ : Basis (Free.ChooseBasisIndex ℤ ↥L) ℤ ↥L := Free.chooseBasis ℤ ↥L
b : Free.ChooseBasisIndex ℤ ↥L → E := Subtype.val ∘ ⇑b₀
this : LinearIndependent ℤ b
⊢ span ℤ (Subtype.val '' Set.range ⇑b₀) = span ℤ (⇑L.subtype '' Set.range ⇑b₀)

Proof state:
case refine_1.intro.intro.intro.intro
K : Type u_1
inst✝⁷ : NormedLinearOrderedField K
inst✝⁶ : HasSolidNorm K
inst✝⁵ : FloorRing K
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : NormedSpace K E
inst✝² : FiniteDimensional K E
inst✝¹ : ProperSpace E
L : Submodule ℤ E
inst✝ : DiscreteTopology ↥L
hs : IsZLattice K L
this✝³ : Module.Finite ℤ ↥L
this✝² : Free ℤ ↥L
this✝¹ : Module ℚ E
b₀ : Basis (Free.ChooseBasisIndex ℤ ↥L) ℤ ↥L := Free.chooseBasis ℤ ↥L
b : Free.ChooseBasisIndex ℤ ↥L → E := Subtype.val ∘ ⇑b₀
this✝ : LinearIndependent ℤ b
h_spanL : span ℤ (Set.range b) = L
h_spanE : span K (Set.range b) = ⊤
h_card : Fintype.card (Free.ChooseBasisIndex ℤ ↥L) = (Set.range b).toFinset.card
t : Set E
ht_inc : t ⊆ Set.range b
ht_span : span K t = span K (Set.range b)
ht_lin : LinearIndependent K Subtype.val
e : Basis (↑t) K E := Basis.mk ht_lin ⋯
this : Fintype ↑t
h : finrank K E < Fintype.card (Free.ChooseBasisIndex ℤ ↥L)
v : E
hv : v ∈ Set.range b \ Set.range ⇑e
⊢ LinearIndepOn ℚ id (Set.range ⇑e) → v ∈ span ℚ (Set.range ⇑e)

Tactic:
intro _

Result:
case refine_1.intro.intro.intro.intro
K : Type u_1
inst✝⁷ : NormedLinearOrderedField K
inst✝⁶ : HasSolidNorm K
inst✝⁵ : FloorRing K
E : Type u_2
inst✝⁴ : NormedAddCommGroup E
inst✝³ : NormedSpace K E
inst✝² : FiniteDimensional K E
inst✝¹ : ProperSpace E
L : Submodule ℤ E
inst✝ : DiscreteTopology ↥L
hs : IsZLattice K L
this✝³ : Module.Finite ℤ ↥L
this✝² : Free ℤ ↥L
this✝¹ : Module ℚ E
b₀ : Basis (Free.ChooseBasisIndex ℤ ↥L) ℤ ↥L := Free.chooseBasis ℤ ↥L
b : Free.ChooseBasisIndex ℤ ↥L → E := Subtype.val ∘ ⇑b₀
this✝ : LinearIndependent ℤ b
h_spanL : span ℤ (Set.range b) = L
h_spanE : span K (Set.range b) = ⊤
h_card : Fintype.card (Free.ChooseBasisIndex ℤ ↥L) = (Set.range b).toFinset.card
t : Set E
ht_inc : t ⊆ Set.range b
ht_span : span K t = span K (Set.range b)
ht_lin : LinearIndependent K Subtype.val
e : Basis (↑t) K E := Basis.mk ht_lin ⋯
this : Fintype ↑t
h : finrank K E < Fintype.card (Free.ChooseBasisIndex ℤ ↥L)
v : E
hv : v ∈ Set.range b \ Set.range ⇑e
a✝ : LinearIndepOn ℚ id (Set.range ⇑e)
⊢ v ∈ span ℚ (Set.range ⇑e)