Description: Obsolete version of mo4 as of 18-Oct-2023. (Contributed by NM, 26-Jul-1995) (New usage is discouraged.) (Proof modification is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | mo4OLD.1 | |- ( x = y -> ( ph <-> ps ) ) |
|
| Assertion | mo4OLD | |- ( E* x ph <-> A. x A. y ( ( ph /\ ps ) -> x = y ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | mo4OLD.1 | |- ( x = y -> ( ph <-> ps ) ) |
|
| 2 | nfv | |- F/ x ps |
|
| 3 | 2 1 | mo4f | |- ( E* x ph <-> A. x A. y ( ( ph /\ ps ) -> x = y ) ) |