induction' p with u' u' v' w' ha p' ih
V : Type u
V' : Type v
V'' : Type w
G : Digraph V
G' : Digraph V'
G'' : Digraph V''
inst✝ : DecidableEq V
u v w : V
p : Walk G v w
h : u ∈ support p
x : V
⊢ List.count (u, x) (edges (takeUntil p u h)) = 0
case nil
V : Type u
V' : Type v
V'' : Type w
G : Digraph V
G' : Digraph V'
G'' : Digraph V''
inst✝ : DecidableEq V
u v w : V
p : Walk G v w
h✝ : u ∈ support p
x u' : V
h : u ∈ support nil
⊢ List.count (u, x) (edges (takeUntil nil u h)) = 0

case cons
V : Type u
V' : Type v
V'' : Type w
G : Digraph V
G' : Digraph V'
G'' : Digraph V''
inst✝ : DecidableEq V
u v w : V
p : Walk G v w
h✝ : u ∈ support p
x u' v' w' : V
ha : G.Adj u' v'
p' : Walk G v' w'
ih : ∀ (h : u ∈ support p'), List.count (u, x) (edges (takeUntil p' u h)) = 0
h : u ∈ support (cons ha p')
⊢ List.count (u, x) (edges (takeUntil (cons ha p') u h)) = 0