Description: Conditions for an extended nonnegative integer to be a positive integer. (Contributed by Thierry Arnoux, 26-Oct-2025)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | xnn0nnd.1 | |- ( ph -> N e. NN0* ) |
|
| xnn0nnd.2 | |- ( ph -> N e. RR ) |
||
| xnn0nnd.3 | |- ( ph -> 0 < N ) |
||
| Assertion | xnn0nnd | |- ( ph -> N e. NN ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | xnn0nnd.1 | |- ( ph -> N e. NN0* ) |
|
| 2 | xnn0nnd.2 | |- ( ph -> N e. RR ) |
|
| 3 | xnn0nnd.3 | |- ( ph -> 0 < N ) |
|
| 4 | 1 2 | xnn0nn0d | |- ( ph -> N e. NN0 ) |
| 5 | elnnnn0b | |- ( N e. NN <-> ( N e. NN0 /\ 0 < N ) ) |
|
| 6 | 4 3 5 | sylanbrc | |- ( ph -> N e. NN ) |