Description: Membership in a positive upper set of integers implies membership in NN . (Contributed by JJ, 1-Oct-2018)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | eluznn | |- ( ( N e. NN /\ M e. ( ZZ>= ` N ) ) -> M e. NN ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | nnuz | |- NN = ( ZZ>= ` 1 ) |
|
| 2 | 1 | uztrn2 | |- ( ( N e. NN /\ M e. ( ZZ>= ` N ) ) -> M e. NN ) |