-- Mathlib/Combinatorics/SetFamily/Compression/UV.lean
theorem compress_injOn : Set.InjOn (compress u v) ↑{a ∈ s | compress u v a ∉ s}

Proof state:
case neg
α : Type u_1
inst✝³ : GeneralizedBooleanAlgebra α
inst✝² : DecidableRel Disjoint
inst✝¹ : DecidableRel fun x1 x2 => x1 ≤ x2
s : Finset α
u v : α
inst✝ : DecidableEq α
a b : α
hb : b ∈ s ∧ compress u v b ∉ s
has : ¬(Disjoint u a ∧ v ≤ a)
ha : a ∈ s ∧ a ∉ s
hab : a = compress u v b
⊢ a = b

Tactic:
exact (ha.2 ha.1).elim

Result:
no goals

Proof state:
case pos
α : Type u_1
inst✝³ : GeneralizedBooleanAlgebra α
inst✝² : DecidableRel Disjoint
inst✝¹ : DecidableRel fun x1 x2 => x1 ≤ x2
s : Finset α
u v : α
inst✝ : DecidableEq α
a b : α
hb : b ∈ s ∧ (if Disjoint u b ∧ v ≤ b then (b ⊔ u) \ v else b) ∉ s
has : Disjoint u a ∧ v ≤ a
ha : a ∈ s ∧ (a ⊔ u) \ v ∉ s
hab : (a ⊔ u) \ v = if Disjoint u b ∧ v ≤ b then (b ⊔ u) \ v else b
⊢ a = b

Tactic:
split_ifs at hb hab with hbs

Result:
case pos
α : Type u_1
inst✝³ : GeneralizedBooleanAlgebra α
inst✝² : DecidableRel Disjoint
inst✝¹ : DecidableRel fun x1 x2 => x1 ≤ x2
s : Finset α
u v : α
inst✝ : DecidableEq α
a b : α
has : Disjoint u a ∧ v ≤ a
ha : a ∈ s ∧ (a ⊔ u) \ v ∉ s
hbs : Disjoint u b ∧ v ≤ b
hb : b ∈ s ∧ (b ⊔ u) \ v ∉ s
hab : (a ⊔ u) \ v = (b ⊔ u) \ v
⊢ a = b

case neg
α : Type u_1
inst✝³ : GeneralizedBooleanAlgebra α
inst✝² : DecidableRel Disjoint
inst✝¹ : DecidableRel fun x1 x2 => x1 ≤ x2
s : Finset α
u v : α
inst✝ : DecidableEq α
a b : α
has : Disjoint u a ∧ v ≤ a
ha : a ∈ s ∧ (a ⊔ u) \ v ∉ s
hbs : ¬(Disjoint u b ∧ v ≤ b)
hb : b ∈ s ∧ b ∉ s
hab : (a ⊔ u) \ v = b
⊢ a = b

Proof state:
α : Type u_1
inst✝³ : GeneralizedBooleanAlgebra α
inst✝² : DecidableRel Disjoint
inst✝¹ : DecidableRel fun x1 x2 => x1 ≤ x2
s : Finset α
u v : α
inst✝ : DecidableEq α
⊢ Set.InjOn (compress u v) ↑(filter (fun a => compress u v a ∉ s) s)

Tactic:
intro a ha b hb hab

Result:
α : Type u_1
inst✝³ : GeneralizedBooleanAlgebra α
inst✝² : DecidableRel Disjoint
inst✝¹ : DecidableRel fun x1 x2 => x1 ≤ x2
s : Finset α
u v : α
inst✝ : DecidableEq α
a : α
ha : a ∈ ↑(filter (fun a => compress u v a ∉ s) s)
b : α
hb : b ∈ ↑(filter (fun a => compress u v a ∉ s) s)
hab : compress u v a = compress u v b
⊢ a = b

Proof state:
α : Type u_1
inst✝³ : GeneralizedBooleanAlgebra α
inst✝² : DecidableRel Disjoint
inst✝¹ : DecidableRel fun x1 x2 => x1 ≤ x2
s : Finset α
u v : α
inst✝ : DecidableEq α
a : α
ha : a ∈ s ∧ compress u v a ∉ s
b : α
hb : b ∈ s ∧ compress u v b ∉ s
hab : compress u v a = compress u v b
⊢ a = b

Tactic:
rw [compress] at ha hab

Result:
α : Type u_1
inst✝³ : GeneralizedBooleanAlgebra α
inst✝² : DecidableRel Disjoint
inst✝¹ : DecidableRel fun x1 x2 => x1 ≤ x2
s : Finset α
u v : α
inst✝ : DecidableEq α
a : α
ha : a ∈ s ∧ (if Disjoint u a ∧ v ≤ a then (a ⊔ u) \ v else a) ∉ s
b : α
hb : b ∈ s ∧ compress u v b ∉ s
hab : (if Disjoint u a ∧ v ≤ a then (a ⊔ u) \ v else a) = compress u v b
⊢ a = b

Proof state:
case pos
α : Type u_1
inst✝³ : GeneralizedBooleanAlgebra α
inst✝² : DecidableRel Disjoint
inst✝¹ : DecidableRel fun x1 x2 => x1 ≤ x2
s : Finset α
u v : α
inst✝ : DecidableEq α
a b : α
hb : b ∈ s ∧ compress u v b ∉ s
has : Disjoint u a ∧ v ≤ a
ha : a ∈ s ∧ (a ⊔ u) \ v ∉ s
hab : (a ⊔ u) \ v = compress u v b
⊢ a = b

Tactic:
rw [compress] at hb hab

Result:
case pos
α : Type u_1
inst✝³ : GeneralizedBooleanAlgebra α
inst✝² : DecidableRel Disjoint
inst✝¹ : DecidableRel fun x1 x2 => x1 ≤ x2
s : Finset α
u v : α
inst✝ : DecidableEq α
a b : α
hb : b ∈ s ∧ (if Disjoint u b ∧ v ≤ b then (b ⊔ u) \ v else b) ∉ s
has : Disjoint u a ∧ v ≤ a
ha : a ∈ s ∧ (a ⊔ u) \ v ∉ s
hab : (a ⊔ u) \ v = if Disjoint u b ∧ v ≤ b then (b ⊔ u) \ v else b
⊢ a = b

Proof state:
α : Type u_1
inst✝³ : GeneralizedBooleanAlgebra α
inst✝² : DecidableRel Disjoint
inst✝¹ : DecidableRel fun x1 x2 => x1 ≤ x2
s : Finset α
u v : α
inst✝ : DecidableEq α
a : α
ha : a ∈ s ∧ (if Disjoint u a ∧ v ≤ a then (a ⊔ u) \ v else a) ∉ s
b : α
hb : b ∈ s ∧ compress u v b ∉ s
hab : (if Disjoint u a ∧ v ≤ a then (a ⊔ u) \ v else a) = compress u v b
⊢ a = b

Tactic:
split_ifs at ha hab with has

Result:
case pos
α : Type u_1
inst✝³ : GeneralizedBooleanAlgebra α
inst✝² : DecidableRel Disjoint
inst✝¹ : DecidableRel fun x1 x2 => x1 ≤ x2
s : Finset α
u v : α
inst✝ : DecidableEq α
a b : α
hb : b ∈ s ∧ compress u v b ∉ s
has : Disjoint u a ∧ v ≤ a
ha : a ∈ s ∧ (a ⊔ u) \ v ∉ s
hab : (a ⊔ u) \ v = compress u v b
⊢ a = b

case neg
α : Type u_1
inst✝³ : GeneralizedBooleanAlgebra α
inst✝² : DecidableRel Disjoint
inst✝¹ : DecidableRel fun x1 x2 => x1 ≤ x2
s : Finset α
u v : α
inst✝ : DecidableEq α
a b : α
hb : b ∈ s ∧ compress u v b ∉ s
has : ¬(Disjoint u a ∧ v ≤ a)
ha : a ∈ s ∧ a ∉ s
hab : a = compress u v b
⊢ a = b

Proof state:
case neg
α : Type u_1
inst✝³ : GeneralizedBooleanAlgebra α
inst✝² : DecidableRel Disjoint
inst✝¹ : DecidableRel fun x1 x2 => x1 ≤ x2
s : Finset α
u v : α
inst✝ : DecidableEq α
a b : α
has : Disjoint u a ∧ v ≤ a
ha : a ∈ s ∧ (a ⊔ u) \ v ∉ s
hbs : ¬(Disjoint u b ∧ v ≤ b)
hb : b ∈ s ∧ b ∉ s
hab : (a ⊔ u) \ v = b
⊢ a = b

Tactic:
exact (hb.2 hb.1).elim

Result:
no goals

Proof state:
α : Type u_1
inst✝³ : GeneralizedBooleanAlgebra α
inst✝² : DecidableRel Disjoint
inst✝¹ : DecidableRel fun x1 x2 => x1 ≤ x2
s : Finset α
u v : α
inst✝ : DecidableEq α
a : α
ha : a ∈ ↑(filter (fun a => compress u v a ∉ s) s)
b : α
hb : b ∈ ↑(filter (fun a => compress u v a ∉ s) s)
hab : compress u v a = compress u v b
⊢ a = b

Tactic:
rw [mem_coe, mem_filter] at ha hb

Result:
α : Type u_1
inst✝³ : GeneralizedBooleanAlgebra α
inst✝² : DecidableRel Disjoint
inst✝¹ : DecidableRel fun x1 x2 => x1 ≤ x2
s : Finset α
u v : α
inst✝ : DecidableEq α
a : α
ha : a ∈ s ∧ compress u v a ∉ s
b : α
hb : b ∈ s ∧ compress u v b ∉ s
hab : compress u v a = compress u v b
⊢ a = b

Proof state:
case pos
α : Type u_1
inst✝³ : GeneralizedBooleanAlgebra α
inst✝² : DecidableRel Disjoint
inst✝¹ : DecidableRel fun x1 x2 => x1 ≤ x2
s : Finset α
u v : α
inst✝ : DecidableEq α
a b : α
has : Disjoint u a ∧ v ≤ a
ha : a ∈ s ∧ (a ⊔ u) \ v ∉ s
hbs : Disjoint u b ∧ v ≤ b
hb : b ∈ s ∧ (b ⊔ u) \ v ∉ s
hab : (a ⊔ u) \ v = (b ⊔ u) \ v
⊢ a = b

Tactic:
exact sup_sdiff_injOn u v has hbs hab

Result:
no goals