specialize hi isCons_of_cons
graph : Graph
start start✝ : Class graph
child₁ : Class.Child start✝
child₂ : Class.Child (Class.Child.class child₁)
subpath₂ : Path graph (Class.Child.class child₂)
hi : isCons (cons child₂ subpath₂) = true → Option.isSome (prefix? (cons child₂ subpath₂)) = true
h : isCons (cons child₁ (cons child₂ subpath₂)) = true
⊢ Option.isSome (prefix? (cons child₁ (cons child₂ subpath₂))) = true
graph : Graph
start start✝ : Class graph
child₁ : Class.Child start✝
child₂ : Class.Child (Class.Child.class child₁)
subpath₂ : Path graph (Class.Child.class child₂)
h : isCons (cons child₁ (cons child₂ subpath₂)) = true
hi : Option.isSome (prefix? (cons child₂ subpath₂)) = true
⊢ Option.isSome (prefix? (cons child₁ (cons child₂ subpath₂))) = true