theorem pimeqe {x: nat} (a: nat) (p: wff x) (q: wff):
$ x = a -> (p <-> q) $ >
$ (P. x x = a -> p) <-> q $;
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | hyp e | x = a -> (p <-> q) |
|
| 2 | 1 | anwr | T. /\ x = a -> (p <-> q) |
| 3 | 2 | pimeqed | T. -> ((P. x x = a -> p) <-> q) |
| 4 | 3 | trud | (P. x x = a -> p) <-> q |