dsimp only [card]
α : Type u
β : Type v
inst✝¹ : BishopFin α
inst✝ : BishopFin β
f : α → β
f_inj : ∀ (a₁ a₂ : α), f a₁ = f a₂ → a₁ = a₂
⊢ card α ≤ card β
α : Type u
β : Type v
inst✝¹ : BishopFin α
inst✝ : BishopFin β
f : α → β
f_inj : ∀ (a₁ a₂ : α), f a₁ = f a₂ → a₁ = a₂
⊢ List.length (elems α) ≤ List.length (elems β)