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Description: Implicit substitution of a class for a setvar variable. (Contributed by NM, 18-Aug-1993)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | vtoclef.1 | |- F/ x ph |
|
| vtoclef.2 | |- A e. _V |
||
| vtoclef.3 | |- ( x = A -> ph ) |
||
| Assertion | vtoclef | |- ph |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | vtoclef.1 | |- F/ x ph |
|
| 2 | vtoclef.2 | |- A e. _V |
|
| 3 | vtoclef.3 | |- ( x = A -> ph ) |
|
| 4 | 2 | isseti | |- E. x x = A |
| 5 | 1 3 | exlimi | |- ( E. x x = A -> ph ) |
| 6 | 4 5 | ax-mp | |- ph |