| Metamath Proof Explorer |
< Previous
Next >
Related theorems Unicode version |
| Description: An inference from transitive law for logical equivalence. |
| Ref | Expression |
|---|---|
| bitr.1 |
|
| bitr.2 |
|
| Ref | Expression |
|---|---|
| bitr |
|
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | bitr.1 |
. . . 4
| |
| 2 | 1 | biimp 133 |
. . 3
|
| 3 | bitr.2 |
. . . 4
| |
| 4 | 3 | biimp 133 |
. . 3
|
| 5 | 2, 4 | syl 12 |
. 2
|
| 6 | 3 | biimpr 134 |
. . 3
|
| 7 | 1 | biimpr 134 |
. . 3
|
| 8 | 6, 7 | syl 12 |
. 2
|
| 9 | 5, 8 | impbi 139 |
1
|