Description: An upper integer set is countable. (Contributed by Glauco Siliprandi, 17-Aug-2020)
Ref | Expression | ||
---|---|---|---|
Hypothesis | uzct.1 | |
|
Assertion | uzct | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | uzct.1 | |
|
2 | uzssz | |
|
3 | 1 2 | eqsstri | |
4 | zex | |
|
5 | ssdomg | |
|
6 | 4 5 | ax-mp | |
7 | 3 6 | ax-mp | |
8 | zct | |
|
9 | domtr | |
|
10 | 7 8 9 | mp2an | |