Metamath Proof Explorer


Theorem o1f

Description: An eventually bounded function is a function. (Contributed by Mario Carneiro, 15-Sep-2014)

Ref Expression
Assertion o1f ⊢ F ∈ 𝑂⁡1 → F : dom ⁡ F ⟶ ℂ

Proof

Step Hyp Ref Expression
1 elo1 ⊢ F ∈ 𝑂⁡1 ↔ F ∈ ℂ ↑ 𝑝𝑚 ℝ ∧ ∃ x ∈ ℝ ∃ m ∈ ℝ ∀ y ∈ dom ⁡ F ∩ x +∞ F ⁡ y ≤ m
2 1 simplbi ⊢ F ∈ 𝑂⁡1 → F ∈ ℂ ↑ 𝑝𝑚 ℝ
3 cnex ⊢ ℂ ∈ V
4 reex ⊢ ℝ ∈ V
5 3 4 elpm2 ⊢ F ∈ ℂ ↑ 𝑝𝑚 ℝ ↔ F : dom ⁡ F ⟶ ℂ ∧ dom ⁡ F ⊆ ℝ
6 5 simplbi ⊢ F ∈ ℂ ↑ 𝑝𝑚 ℝ → F : dom ⁡ F ⟶ ℂ
7 2 6 syl ⊢ F ∈ 𝑂⁡1 → F : dom ⁡ F ⟶ ℂ