Description: Equivalent wff's yield equal ordered-pair class abstractions (deduction form). (Contributed by NM, 21-Feb-2004) (Proof shortened by Andrew Salmon, 9-Jul-2011)
Ref | Expression | ||
---|---|---|---|
Hypotheses | opabbid.1 | |
|
opabbid.2 | |
||
opabbid.3 | |
||
Assertion | opabbid | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | opabbid.1 | |
|
2 | opabbid.2 | |
|
3 | opabbid.3 | |
|
4 | 3 | anbi2d | |
5 | 2 4 | exbid | |
6 | 1 5 | exbid | |
7 | 6 | abbidv | |
8 | df-opab | |
|
9 | df-opab | |
|
10 | 7 8 9 | 3eqtr4g | |