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Description: Inference from Theorem 19.23 of Margaris p. 90, for three restricted quantifiers. (Contributed by AV, 23-Aug-2025)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | rexlimdvvva.1 | |- ( ( ph /\ ( x e. A /\ y e. B /\ z e. C ) ) -> ( ps -> ch ) ) |
|
| Assertion | rexlimdvvva | |- ( ph -> ( E. x e. A E. y e. B E. z e. C ps -> ch ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | rexlimdvvva.1 | |- ( ( ph /\ ( x e. A /\ y e. B /\ z e. C ) ) -> ( ps -> ch ) ) |
|
| 2 | df-3an | |- ( ( x e. A /\ y e. B /\ z e. C ) <-> ( ( x e. A /\ y e. B ) /\ z e. C ) ) |
|
| 3 | 1 | ex | |- ( ph -> ( ( x e. A /\ y e. B /\ z e. C ) -> ( ps -> ch ) ) ) |
| 4 | 2 3 | biimtrrid | |- ( ph -> ( ( ( x e. A /\ y e. B ) /\ z e. C ) -> ( ps -> ch ) ) ) |
| 5 | 4 | expdimp | |- ( ( ph /\ ( x e. A /\ y e. B ) ) -> ( z e. C -> ( ps -> ch ) ) ) |
| 6 | 5 | rexlimdv | |- ( ( ph /\ ( x e. A /\ y e. B ) ) -> ( E. z e. C ps -> ch ) ) |
| 7 | 6 | rexlimdvva | |- ( ph -> ( E. x e. A E. y e. B E. z e. C ps -> ch ) ) |