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Description: Lemma for renegeu and similar. Derive existential uniqueness from existence. (Contributed by Steven Nguyen, 28-Jan-2023)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | renegeulemv.b | |- ( ph -> B e. RR ) |
|
| renegeulemv.1 | |- ( ph -> E. y e. RR ( B + y ) = A ) |
||
| Assertion | renegeulemv | |- ( ph -> E! x e. RR ( B + x ) = A ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | renegeulemv.b | |- ( ph -> B e. RR ) |
|
| 2 | renegeulemv.1 | |- ( ph -> E. y e. RR ( B + y ) = A ) |
|
| 3 | simprl | |- ( ( ph /\ ( y e. RR /\ ( B + y ) = A ) ) -> y e. RR ) |
|
| 4 | simplrr | |- ( ( ( ph /\ ( y e. RR /\ ( B + y ) = A ) ) /\ x e. RR ) -> ( B + y ) = A ) |
|
| 5 | 4 | eqcomd | |- ( ( ( ph /\ ( y e. RR /\ ( B + y ) = A ) ) /\ x e. RR ) -> A = ( B + y ) ) |
| 6 | 5 | eqeq2d | |- ( ( ( ph /\ ( y e. RR /\ ( B + y ) = A ) ) /\ x e. RR ) -> ( ( B + x ) = A <-> ( B + x ) = ( B + y ) ) ) |
| 7 | simpr | |- ( ( ( ph /\ ( y e. RR /\ ( B + y ) = A ) ) /\ x e. RR ) -> x e. RR ) |
|
| 8 | simplrl | |- ( ( ( ph /\ ( y e. RR /\ ( B + y ) = A ) ) /\ x e. RR ) -> y e. RR ) |
|
| 9 | 1 | ad2antrr | |- ( ( ( ph /\ ( y e. RR /\ ( B + y ) = A ) ) /\ x e. RR ) -> B e. RR ) |
| 10 | readdcan | |- ( ( x e. RR /\ y e. RR /\ B e. RR ) -> ( ( B + x ) = ( B + y ) <-> x = y ) ) |
|
| 11 | 7 8 9 10 | syl3anc | |- ( ( ( ph /\ ( y e. RR /\ ( B + y ) = A ) ) /\ x e. RR ) -> ( ( B + x ) = ( B + y ) <-> x = y ) ) |
| 12 | 6 11 | bitrd | |- ( ( ( ph /\ ( y e. RR /\ ( B + y ) = A ) ) /\ x e. RR ) -> ( ( B + x ) = A <-> x = y ) ) |
| 13 | 12 | ralrimiva | |- ( ( ph /\ ( y e. RR /\ ( B + y ) = A ) ) -> A. x e. RR ( ( B + x ) = A <-> x = y ) ) |
| 14 | reu6i | |- ( ( y e. RR /\ A. x e. RR ( ( B + x ) = A <-> x = y ) ) -> E! x e. RR ( B + x ) = A ) |
|
| 15 | 3 13 14 | syl2anc | |- ( ( ph /\ ( y e. RR /\ ( B + y ) = A ) ) -> E! x e. RR ( B + x ) = A ) |
| 16 | 2 15 | rexlimddv | |- ( ph -> E! x e. RR ( B + x ) = A ) |