no goals
ι : Sort ?u.266848
V : Type u
W : Type v
G : SimpleGraph V
G' : Subgraph G
s✝ s s' : Set V
⊢ deleteVerts (deleteVerts G' s) s' = deleteVerts G' (s ∪ s')
ext <;> simp (config := { contextual := true }) [not_or, and_assoc]