simp at h1
v u : VarName
T : Finset VarName
h2 : v ∉ T
X : DefName
xs : List VarName
S : Finset VarName
h1 : v ∈ xs ∧ v ∉ S ∪ T → u ∉ S ∪ T
⊢ v ∈ xs ∧ v ∉ S → u ∉ S
v u : VarName
T : Finset VarName
h2 : v ∉ T
X : DefName
xs : List VarName
S : Finset VarName
h1 : v ∈ xs → v ∉ S → v ∉ T → u ∉ S ∧ u ∉ T
⊢ v ∈ xs ∧ v ∉ S → u ∉ S