Description: Two is an element of a nonempty Tarski class. (Contributed by FL, 22-Feb-2011) (Proof shortened by Mario Carneiro, 20-Sep-2014)
Ref | Expression | ||
---|---|---|---|
Assertion | tsk2 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | tsk1 | |
|
2 | df-2o | |
|
3 | 1on | |
|
4 | tsksuc | |
|
5 | 3 4 | mp3an2 | |
6 | 2 5 | eqeltrid | |
7 | 1 6 | syldan | |