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Metamath Proof Explorer
Theorem 4z
Description: 4 is an integer. (Contributed by BJ, 26-Mar-2020)
|
|
Ref |
Expression |
|
Assertion |
4z |
⊢ 4 ∈ ℤ |
Proof
| Step |
Hyp |
Ref |
Expression |
| 1 |
|
4nn |
⊢ 4 ∈ ℕ |
| 2 |
1
|
nnzi |
⊢ 4 ∈ ℤ |