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 |