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Related theorems Unicode version |
| Description: Deduction joining two equivalences to form equivalence of implications. |
| Ref | Expression |
|---|---|
| bi12d.1 |
|
| bi12d.2 |
|
| Ref | Expression |
|---|---|
| imbi12d |
|
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | bi12d.1 |
. . 3
| |
| 2 | 1 | imbi1d 611 |
. 2
|
| 3 | bi12d.2 |
. . 3
| |
| 4 | 3 | imbi2d 610 |
. 2
|
| 5 | 2, 4 | bitrd 526 |
1
|