English
If h is an inclusion of graphs, then p.mapLe h preserves the IsTrail property, i.e., (p.mapLe h).IsTrail iff p.IsTrail.
Русский
Если h — вложение графов, отображение p.mapLe h сохраняет свойство IsTrail, то есть (p.mapLe h).IsTrail эквивалентно p.IsTrail.
LaTeX
$$$ \forall {G G' : SimpleGraph V} (h : G \le G') {u v : V} {p : G.Walk u v}, \n \text{mapLe isTrail equivalence}\n \Rightarrow (p.mapLe h).IsTrail \iff p.IsTrail$$$
Lean4
@[simp]
theorem mapLe_isTrail {G G' : SimpleGraph V} (h : G ≤ G') {u v : V} {p : G.Walk u v} :
(p.mapLe h).IsTrail ↔ p.IsTrail :=
map_isTrail_iff_of_injective Function.injective_id