theorem sbneh {x: nat} (a: nat) (b c: nat x):
$ FN/ x c $ >
$ x = a -> b = c $ >
$ N[a / x] b = c $;
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | hyp h | FN/ x c |
|
| 2 | 1 | sbneht | A. x (x = a -> b = c) -> N[a / x] b = c |
| 3 | hyp e | x = a -> b = c |
|
| 4 | 3 | ax_gen | A. x (x = a -> b = c) |
| 5 | 2, 4 | ax_mp | N[a / x] b = c |