Theorem 3z

Description: 3 is an integer. (Contributed by David A. Wheeler, 8-Dec-2018)

	Ref	Expression
Assertion	3z	⊢ 3 ∈ ℤ

Proof

Step	Hyp	Ref	Expression
1		3nn	⊢ 3 ∈ ℕ
2	1	nnzi	⊢ 3 ∈ ℤ