theorem nfrlam {x y: nat} (a b: nat x y):
$ FN/ x a $ >
$ FN/ x b $ >
$ FN/ x \. y e. a, b $;
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | hyp h2 | FN/ x b |
|
| 2 | 1 | nflam | FS/ x \ y, b |
| 3 | hyp h1 | FN/ x a |
|
| 4 | 3 | nfns | FS/ x a |
| 5 | 2, 4 | nfres | FS/ x (\ y, b) |` a |
| 6 | 5 | nflower | FN/ x lower ((\ y, b) |` a) |
| 7 | 6 | conv rlam | FN/ x \. y e. a, b |