Theorem nn0zd

Description: A positive integer is an integer. (Contributed by Mario Carneiro, 28-May-2016)

	Ref	Expression
Hypothesis	nn0zd.1	⊢ ( 𝜑 → 𝐴 ∈ ℕ0 )
Assertion	nn0zd	⊢ ( 𝜑 → 𝐴 ∈ ℤ )

Proof

Step	Hyp	Ref	Expression
1		nn0zd.1	⊢ ( 𝜑 → 𝐴 ∈ ℕ0 )
2		nn0ssz	⊢ ℕ0 ⊆ ℤ
3	2 1	sseldi	⊢ ( 𝜑 → 𝐴 ∈ ℤ )