English
If p is a walk from u to v and h is an adjacency from u to v, then the tail of p.cons h is the same as the tail of p (up to reindexing): (p.cons h).tail = p.copy (getVert_zero p).symm rfl.
Русский
Пусть p — ход от u к v, и h — смежность; хвост хода p cons h совпадает с хвостом p (с учётом переназначения первого вершины).
LaTeX
$$$ (p.cons\\ h).tail = p.copy (getVert_zero p).symm rfl $$$
Lean4
@[simp]
theorem tail_cons (h : G.Adj u v) (p : G.Walk v w) : (p.cons h).tail = p.copy (getVert_zero p).symm rfl := by
match p with
| .nil => rfl
| .cons h q => rfl