Description: Deduction from equality to equivalence of membership. (Contributed by NM, 31-May-1994)
Ref | Expression | ||
---|---|---|---|
Hypotheses | eleq12d.1 | |
|
eleq12d.2 | |
||
Assertion | eleq12d | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | eleq12d.1 | |
|
2 | eleq12d.2 | |
|
3 | 2 | eleq2d | |
4 | 1 | eleq1d | |
5 | 3 4 | bitrd | |