English
A copy induces an embedding from the neighbor set of a vertex to the neighbor set of its image.
Русский
Копия индуцирует вложение множеств соседей вершины в множество соседей образа вершины.
LaTeX
$$(f : Copy A B) (a : α) : A.neighborSet a ↪ B.neighborSet (f a)$$
Lean4
/-- A copy induces an embedding of neighbor sets. -/
def mapNeighborSet (f : Copy A B) (a : α) : A.neighborSet a ↪ B.neighborSet (f a)
where
toFun v := ⟨f v, f.toHom.apply_mem_neighborSet v.prop⟩
inj' _ _
h := by
rw [Subtype.mk_eq_mk] at h ⊢
exact f.injective h