simp only [mem_support_iff, mem_tail_support_append_iff]
V : Type u
V' : Type v
V'' : Type w
G : Digraph V
G' : Digraph V'
G'' : Digraph V''
t u v w : V
p : Walk G u v
p' : Walk G v w
⊢ t ∈ support (append p p') ↔ t ∈ support p ∨ t ∈ support p'
V : Type u
V' : Type v
V'' : Type w
G : Digraph V
G' : Digraph V'
G'' : Digraph V''
t u v w : V
p : Walk G u v
p' : Walk G v w
⊢ t = u ∨ t ∈ List.tail (support p) ∨ t ∈ List.tail (support p') ↔
    (t = u ∨ t ∈ List.tail (support p)) ∨ t = v ∨ t ∈ List.tail (support p')