Description: Existential quantification over a class abstraction. (Contributed by Mario Carneiro, 23-Jan-2014) (Revised by Mario Carneiro, 3-Sep-2015)
Ref | Expression | ||
---|---|---|---|
Hypothesis | ralab.1 | ||
Assertion | rexab |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ralab.1 | ||
2 | df-rex | ||
3 | vex | ||
4 | 3 1 | elab | |
5 | 4 | anbi1i | |
6 | 5 | exbii | |
7 | 2 6 | bitri |