**Description:** The set of positive integers exists. (Contributed by NM, 3-Oct-1999)
(Revised by Mario Carneiro, 17-Nov-2014)

Ref | Expression | ||
---|---|---|---|

Assertion | nnex | ⊢ ℕ ∈ V |

Step | Hyp | Ref | Expression |
---|---|---|---|

1 | cnex | ⊢ ℂ ∈ V | |

2 | nnsscn | ⊢ ℕ ⊆ ℂ | |

3 | 1 2 | ssexi | ⊢ ℕ ∈ V |