Theorem nnz

Description: A positive integer is an integer. (Contributed by NM, 9-May-2004)

	Ref	Expression
Assertion	nnz	⊢ ( 𝑁 ∈ ℕ → 𝑁 ∈ ℤ )

Proof

Step	Hyp	Ref	Expression
1		nnssz	⊢ ℕ ⊆ ℤ
2	1	sseli	⊢ ( 𝑁 ∈ ℕ → 𝑁 ∈ ℤ )