Description: Obsolete version of nfnaew as of 25-Sep-2024. (Contributed by Mario Carneiro, 11-Aug-2016) (Revised by Gino Giotto, 10-Jan-2024) (Proof modification is discouraged.) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | nfnaewOLD | |- F/ z -. A. x x = y |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | hbaev | |- ( A. x x = y -> A. z A. x x = y ) |
|
| 2 | 1 | nf5i | |- F/ z A. x x = y |
| 3 | 2 | nfn | |- F/ z -. A. x x = y |