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

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 ℤ id (Set.range b)

Tactic:
suffices ¬ LinearIndepOn ℤ id (insert v (Set.range e)) by
  contrapose! this
  refine this.mono ?_
  exact Set.insert_subset (Set.mem_of_mem_diff hv) (by simp [e, ht_inc])

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
⊢ ¬LinearIndepOn ℤ id (insert v (Set.range ⇑e))

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✝¹ : Module.Finite ℤ ↥L
this✝ : Free ℤ ↥L
this : Module ℚ E
b₀ : Basis (Free.ChooseBasisIndex ℤ ↥L) ℤ ↥L := Free.chooseBasis ℤ ↥L
⊢ finrank ℤ ↥L = finrank K E

Tactic:
let b := Subtype.val ∘ b₀

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✝¹ : Module.Finite ℤ ↥L
this✝ : 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
⊢ finrank ℤ ↥L = finrank K E

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 : 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)
⊢ Set.MapsTo (fun n => fract e (n • v)) Set.univ (Metric.closedBall 0 (∑ i : ↑t, ‖e i‖) ∩ ↑L)

Tactic:
rw [Set.mapsTo_inter, Set.mapsTo_univ_iff, Set.mapsTo_univ_iff]

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 : 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), fract e (x • v) ∈ Metric.closedBall 0 (∑ i : ↑t, ‖e i‖)) ∧ ∀ (x : ℤ), fract e (x • v) ∈ ↑L

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✝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) = ⊤
⊢ Function.Injective b

Tactic:
exact Subtype.coe_injective.comp (Basis.injective _)

Result:
no goals