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Description: Rule of specialization, using implicit substitution. Compare Theorem 7.3 of Quine p. 44. (Contributed by NM, 22-Jun-1994) Avoid ax-10 , ax-11 . (Revised by Wolf Lammen, 25-Aug-2023)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | spcgv.1 | |- ( x = A -> ( ph <-> ps ) ) |
|
| Assertion | spcgv | |- ( A e. V -> ( A. x ph -> ps ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | spcgv.1 | |- ( x = A -> ( ph <-> ps ) ) |
|
| 2 | elex | |- ( A e. V -> A e. _V ) |
|
| 3 | id | |- ( A e. _V -> A e. _V ) |
|
| 4 | 1 | adantl | |- ( ( A e. _V /\ x = A ) -> ( ph <-> ps ) ) |
| 5 | 3 4 | spcdv | |- ( A e. _V -> ( A. x ph -> ps ) ) |
| 6 | 2 5 | syl | |- ( A e. V -> ( A. x ph -> ps ) ) |