exact h.symm
graph✝ : Graph
cls✝ : Class graph✝
c₁ : Class.Child cls✝
c₂ : Class.Child (Class.Child.class c₁)
path₁ : Path graph✝ (Class.Child.class c₂)
path₂ : Path graph✝ cls✝
subpath : Path graph✝ (Class.Child.class c₁)
hp : prefix? (cons c₂ path₁) = some subpath
h : cons c₁ subpath = path₂
⊢ path₂ = cons c₁ subpath
no goals