theorem alimd {x: nat} (G: wff) (a b: wff x):
$ G -> a -> b $ >
$ G -> A. x a -> A. x b $;
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ax_4 | A. x (a -> b) -> A. x a -> A. x b |
|
| 2 | hyp h | G -> a -> b |
|
| 3 | 2 | alimi | A. x G -> A. x (a -> b) |
| 4 | ax_5 | G -> A. x G |
|
| 5 | 3, 4 | syl | G -> A. x (a -> b) |
| 6 | 1, 5 | syl | G -> A. x a -> A. x b |