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Description: Technical lemma for bnj60 . This lemma may no longer be used or have become an indirect lemma of the theorem in question (i.e. a lemma of a lemma... of the theorem). (Contributed by Jonathan Ben-Naim, 3-Jun-2011) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | bnj1234.2 | |- Y = <. x , ( f |` _pred ( x , A , R ) ) >. |
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| bnj1234.3 | |- C = { f | E. d e. B ( f Fn d /\ A. x e. d ( f ` x ) = ( G ` Y ) ) } |
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| bnj1234.4 | |- Z = <. x , ( g |` _pred ( x , A , R ) ) >. |
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| bnj1234.5 | |- D = { g | E. d e. B ( g Fn d /\ A. x e. d ( g ` x ) = ( G ` Z ) ) } |
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| Assertion | bnj1234 | |- C = D |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | bnj1234.2 | |- Y = <. x , ( f |` _pred ( x , A , R ) ) >. |
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| 2 | bnj1234.3 | |- C = { f | E. d e. B ( f Fn d /\ A. x e. d ( f ` x ) = ( G ` Y ) ) } |
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| 3 | bnj1234.4 | |- Z = <. x , ( g |` _pred ( x , A , R ) ) >. |
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| 4 | bnj1234.5 | |- D = { g | E. d e. B ( g Fn d /\ A. x e. d ( g ` x ) = ( G ` Z ) ) } |
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| 5 | fneq1 | |- ( f = g -> ( f Fn d <-> g Fn d ) ) |
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| 6 | fveq1 | |- ( f = g -> ( f ` x ) = ( g ` x ) ) |
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| 7 | reseq1 | |- ( f = g -> ( f |` _pred ( x , A , R ) ) = ( g |` _pred ( x , A , R ) ) ) |
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| 8 | 7 | opeq2d | |- ( f = g -> <. x , ( f |` _pred ( x , A , R ) ) >. = <. x , ( g |` _pred ( x , A , R ) ) >. ) |
| 9 | 8 1 3 | 3eqtr4g | |- ( f = g -> Y = Z ) |
| 10 | 9 | fveq2d | |- ( f = g -> ( G ` Y ) = ( G ` Z ) ) |
| 11 | 6 10 | eqeq12d | |- ( f = g -> ( ( f ` x ) = ( G ` Y ) <-> ( g ` x ) = ( G ` Z ) ) ) |
| 12 | 11 | ralbidv | |- ( f = g -> ( A. x e. d ( f ` x ) = ( G ` Y ) <-> A. x e. d ( g ` x ) = ( G ` Z ) ) ) |
| 13 | 5 12 | anbi12d | |- ( f = g -> ( ( f Fn d /\ A. x e. d ( f ` x ) = ( G ` Y ) ) <-> ( g Fn d /\ A. x e. d ( g ` x ) = ( G ` Z ) ) ) ) |
| 14 | 13 | rexbidv | |- ( f = g -> ( E. d e. B ( f Fn d /\ A. x e. d ( f ` x ) = ( G ` Y ) ) <-> E. d e. B ( g Fn d /\ A. x e. d ( g ` x ) = ( G ` Z ) ) ) ) |
| 15 | 14 | cbvabv | |- { f | E. d e. B ( f Fn d /\ A. x e. d ( f ` x ) = ( G ` Y ) ) } = { g | E. d e. B ( g Fn d /\ A. x e. d ( g ` x ) = ( G ` Z ) ) } |
| 16 | 15 2 4 | 3eqtr4i | |- C = D |