Description: An integer greater than or equal to 3 is a positive integer. (Contributed by Alexander van der Vekens, 17-Sep-2018) (Proof shortened by AV, 30-Nov-2025)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | eluz3nn | |- ( N e. ( ZZ>= ` 3 ) -> N e. NN ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | uzuzle23 | |- ( N e. ( ZZ>= ` 3 ) -> N e. ( ZZ>= ` 2 ) ) |
|
| 2 | eluz2nn | |- ( N e. ( ZZ>= ` 2 ) -> N e. NN ) |
|
| 3 | 1 2 | syl | |- ( N e. ( ZZ>= ` 3 ) -> N e. NN ) |