Description: A positive integer is an integer. (Contributed by Mario Carneiro, 18-Feb-2014)
Ref | Expression | ||
---|---|---|---|
Hypothesis | nnzi.1 | ⊢ 𝑁 ∈ ℕ | |
Assertion | nnzi | ⊢ 𝑁 ∈ ℤ |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | nnzi.1 | ⊢ 𝑁 ∈ ℕ | |
2 | nnssz | ⊢ ℕ ⊆ ℤ | |
3 | 2 1 | sselii | ⊢ 𝑁 ∈ ℤ |