-- Mathlib/Algebra/Module/ZLattice/Basic.lean
theorem Zlattice.FG [hs : IsZLattice K L] : L.FG

Proof state:
case intro.intro.intro.refine_1
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
s : Set E
h_incl : s ⊆ ↑L
h_span : span K s = span K ↑L
h_lind : LinearIndependent K Subtype.val
b : Basis { x // x ∈ s } K E := Basis.mk h_lind ⋯
this : Fintype ↑s
⊢ (↑(Submodule.map (span ℤ (Set.range ⇑b)).mkQ L)).Finite

Tactic:
refine Set.Finite.of_finite_image (f := ((↑) : _ →  E) ∘ quotientEquiv b) ?_
  (Function.Injective.injOn (Subtype.coe_injective.comp (quotientEquiv b).injective))

Result:
case intro.intro.intro.refine_1
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
s : Set E
h_incl : s ⊆ ↑L
h_span : span K s = span K ↑L
h_lind : LinearIndependent K Subtype.val
b : Basis { x // x ∈ s } K E := Basis.mk h_lind ⋯
this : Fintype ↑s
⊢ (Subtype.val ∘ ⇑(quotientEquiv b) '' ↑(Submodule.map (span ℤ (Set.range ⇑b)).mkQ L)).Finite

Proof state:
case intro.intro.intro.refine_1
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
s : Set E
h_incl : s ⊆ ↑L
h_span : span K s = span K ↑L
h_lind : LinearIndependent K Subtype.val
b : Basis { x // x ∈ s } K E := Basis.mk h_lind ⋯
this✝ : Fintype ↑s
this : (fundamentalDomain b ∩ ↑L).Finite
⊢ Subtype.val ∘ ⇑(quotientEquiv b) '' ↑(Submodule.map (span ℤ (Set.range ⇑b)).mkQ L) ⊆ fundamentalDomain b ∩ ↑L

Tactic:
rintro _ ⟨_, ⟨⟨x, ⟨h_mem, rfl⟩⟩, rfl⟩⟩

Result:
case intro.intro.intro.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
s : Set E
h_incl : s ⊆ ↑L
h_span : span K s = span K ↑L
h_lind : LinearIndependent K Subtype.val
b : Basis { x // x ∈ s } K E := Basis.mk h_lind ⋯
this✝ : Fintype ↑s
this : (fundamentalDomain b ∩ ↑L).Finite
x : E
h_mem : x ∈ ↑L
⊢ (Subtype.val ∘ ⇑(quotientEquiv b)) ((span ℤ (Set.range ⇑b)).mkQ x) ∈ fundamentalDomain b ∩ ↑L

Proof state:
case intro.intro.intro.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
s : Set E
h_incl : s ⊆ ↑L
h_span : span K s = span K ↑L
h_lind : LinearIndependent K Subtype.val
b : Basis { x // x ∈ s } K E := Basis.mk h_lind ⋯
this✝ : Fintype ↑s
this : (fundamentalDomain b ∩ ↑L).Finite
x : E
h_mem : x ∈ ↑L
⊢ fract b x ∈ fundamentalDomain b ∩ ↑L

Tactic:
refine ⟨?_, ?_⟩

Result:
case intro.intro.intro.refine_1.intro.intro.intro.intro.refine_1
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
s : Set E
h_incl : s ⊆ ↑L
h_span : span K s = span K ↑L
h_lind : LinearIndependent K Subtype.val
b : Basis { x // x ∈ s } K E := Basis.mk h_lind ⋯
this✝ : Fintype ↑s
this : (fundamentalDomain b ∩ ↑L).Finite
x : E
h_mem : x ∈ ↑L
⊢ fract b x ∈ fundamentalDomain b

case intro.intro.intro.refine_1.intro.intro.intro.intro.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
s : Set E
h_incl : s ⊆ ↑L
h_span : span K s = span K ↑L
h_lind : LinearIndependent K Subtype.val
b : Basis { x // x ∈ s } K E := Basis.mk h_lind ⋯
this✝ : Fintype ↑s
this : (fundamentalDomain b ∩ ↑L).Finite
x : E
h_mem : x ∈ ↑L
⊢ fract b x ∈ ↑L

Proof state:
case intro.intro.intro.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
s : Set E
h_incl : s ⊆ ↑L
h_span : span K s = span K ↑L
h_lind : LinearIndependent K Subtype.val
⊢ (span ℤ s).FG

Tactic:
exact fg_span (LinearIndependent.setFinite h_lind)

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
⊢ L.FG

Tactic:
obtain ⟨s, ⟨h_incl, ⟨h_span, h_lind⟩⟩⟩ := exists_linearIndependent K (L : Set E)

Result:
case 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
s : Set E
h_incl : s ⊆ ↑L
h_span : span K s = span K ↑L
h_lind : LinearIndependent K Subtype.val
⊢ L.FG

Proof state:
case intro.intro.intro.refine_1
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
s : Set E
h_incl : s ⊆ ↑L
h_span : span K s = span K ↑L
h_lind : LinearIndependent K Subtype.val
b : Basis { x // x ∈ s } K E := Basis.mk h_lind ⋯
⊢ (↑(Submodule.map (span ℤ s).mkQ L)).Finite

Tactic:
rw [show span ℤ s = span ℤ (Set.range b) by simp [b, Basis.coe_mk, Subtype.range_coe_subtype]]

Result:
case intro.intro.intro.refine_1
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
s : Set E
h_incl : s ⊆ ↑L
h_span : span K s = span K ↑L
h_lind : LinearIndependent K Subtype.val
b : Basis { x // x ∈ s } K E := Basis.mk h_lind ⋯
⊢ (↑(Submodule.map (span ℤ (Set.range ⇑b)).mkQ L)).Finite