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Related theorems Unicode version |
| Description: Equality implies equivalence of equalities. |
| Ref | Expression |
|---|---|
| eqeq1 |
|
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | dfcleq 1470 |
. . . . . 6
| |
| 2 | 1 | biimp 151 |
. . . . 5
|
| 3 | 2 | 19.21bi 1060 |
. . . 4
|
| 4 | 3 | bibi1d 619 |
. . 3
|
| 5 | 4 | albidv 1278 |
. 2
|
| 6 | dfcleq 1470 |
. 2
| |
| 7 | dfcleq 1470 |
. 2
| |
| 8 | 5, 6, 7 | 3bitr4g 555 |
1
|