This is an inofficial mirror of http://metamath.tirix.org for personal testing of a visualizer extension only.

Metamath Proof Explorer

Theorem 2z

Description: 2 is an integer. (Contributed by NM, 10-May-2004)

Ref Expression
Assertion 2z 2 ∈ ℤ

Proof

Step Hyp Ref Expression
1 2nn ⊢ 2 ∈ ℕ
2 1 nnzi ⊢ 2 ∈ ℤ