Theorem: Digraph.Walk.IsTrail.of_append_left (GraphProjects/DigraphConnectivity.lean)

State before:
V : Type u
V' : Type v
V'' : Type w
G : Digraph V
G' : Digraph V'
G'' : Digraph V''
u v w : V
p : Walk G u v
q : Walk G v w
h : IsTrail (append p q)
⊢ IsTrail p
Tactic:
rw [isTrail_def, edges_append, List.nodup_append] at h
State after:
V : Type u
V' : Type v
V'' : Type w
G : Digraph V
G' : Digraph V'
G'' : Digraph V''
u v w : V
p : Walk G u v
q : Walk G v w
h : List.Nodup (edges p) ∧ List.Nodup (edges q) ∧ List.Disjoint (edges p) (edges q)
⊢ IsTrail p

State before:
V : Type u
V' : Type v
V'' : Type w
G : Digraph V
G' : Digraph V'
G'' : Digraph V''
u v w : V
p : Walk G u v
q : Walk G v w
h : List.Nodup (edges p) ∧ List.Nodup (edges q) ∧ List.Disjoint (edges p) (edges q)
⊢ IsTrail p
Tactic:
exact ⟨h.1⟩
State after:
no goals