This is an inofficial mirror of http://metamath.tirix.org for personal testing of a visualizer extension only.
Metamath Proof Explorer
Description: A positive integer is an integer. (Contributed by Mario Carneiro, 28-May-2016)
|
|
Ref |
Expression |
|
Hypothesis |
nnzd.1 |
|- ( ph -> A e. NN ) |
|
Assertion |
nnzd |
|- ( ph -> A e. ZZ ) |
Proof
| Step |
Hyp |
Ref |
Expression |
| 1 |
|
nnzd.1 |
|- ( ph -> A e. NN ) |
| 2 |
1
|
nnnn0d |
|- ( ph -> A e. NN0 ) |
| 3 |
2
|
nn0zd |
|- ( ph -> A e. ZZ ) |