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Description: Technical lemma for bnj852 . 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 | ||
|---|---|---|---|
| Hypothesis | bnj591.1 | |- ( th <-> ( ( n e. D /\ ch /\ ch' ) -> ( f ` j ) = ( g ` j ) ) ) |
|
| Assertion | bnj591 | |- ( [. k / j ]. th <-> ( ( n e. D /\ ch /\ ch' ) -> ( f ` k ) = ( g ` k ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | bnj591.1 | |- ( th <-> ( ( n e. D /\ ch /\ ch' ) -> ( f ` j ) = ( g ` j ) ) ) |
|
| 2 | 1 | sbcbii | |- ( [. k / j ]. th <-> [. k / j ]. ( ( n e. D /\ ch /\ ch' ) -> ( f ` j ) = ( g ` j ) ) ) |
| 3 | vex | |- k e. _V |
|
| 4 | fveq2 | |- ( j = k -> ( f ` j ) = ( f ` k ) ) |
|
| 5 | fveq2 | |- ( j = k -> ( g ` j ) = ( g ` k ) ) |
|
| 6 | 4 5 | eqeq12d | |- ( j = k -> ( ( f ` j ) = ( g ` j ) <-> ( f ` k ) = ( g ` k ) ) ) |
| 7 | 6 | imbi2d | |- ( j = k -> ( ( ( n e. D /\ ch /\ ch' ) -> ( f ` j ) = ( g ` j ) ) <-> ( ( n e. D /\ ch /\ ch' ) -> ( f ` k ) = ( g ` k ) ) ) ) |
| 8 | 3 7 | sbcie | |- ( [. k / j ]. ( ( n e. D /\ ch /\ ch' ) -> ( f ` j ) = ( g ` j ) ) <-> ( ( n e. D /\ ch /\ ch' ) -> ( f ` k ) = ( g ` k ) ) ) |
| 9 | 2 8 | bitri | |- ( [. k / j ]. th <-> ( ( n e. D /\ ch /\ ch' ) -> ( f ` k ) = ( g ` k ) ) ) |