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Description: The kernel of a functional. (Contributed by NM, 15-Apr-2014) (Revised by Mario Carneiro, 24-Jun-2014)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | lkrfval.d | |- D = ( Scalar ` W ) |
|
| lkrfval.o | |- .0. = ( 0g ` D ) |
||
| lkrfval.f | |- F = ( LFnl ` W ) |
||
| lkrfval.k | |- K = ( LKer ` W ) |
||
| Assertion | lkrfval | |- ( W e. X -> K = ( f e. F |-> ( `' f " { .0. } ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | lkrfval.d | |- D = ( Scalar ` W ) |
|
| 2 | lkrfval.o | |- .0. = ( 0g ` D ) |
|
| 3 | lkrfval.f | |- F = ( LFnl ` W ) |
|
| 4 | lkrfval.k | |- K = ( LKer ` W ) |
|
| 5 | elex | |- ( W e. X -> W e. _V ) |
|
| 6 | fveq2 | |- ( w = W -> ( LFnl ` w ) = ( LFnl ` W ) ) |
|
| 7 | 6 3 | eqtr4di | |- ( w = W -> ( LFnl ` w ) = F ) |
| 8 | fveq2 | |- ( w = W -> ( Scalar ` w ) = ( Scalar ` W ) ) |
|
| 9 | 8 1 | eqtr4di | |- ( w = W -> ( Scalar ` w ) = D ) |
| 10 | 9 | fveq2d | |- ( w = W -> ( 0g ` ( Scalar ` w ) ) = ( 0g ` D ) ) |
| 11 | 10 2 | eqtr4di | |- ( w = W -> ( 0g ` ( Scalar ` w ) ) = .0. ) |
| 12 | 11 | sneqd | |- ( w = W -> { ( 0g ` ( Scalar ` w ) ) } = { .0. } ) |
| 13 | 12 | imaeq2d | |- ( w = W -> ( `' f " { ( 0g ` ( Scalar ` w ) ) } ) = ( `' f " { .0. } ) ) |
| 14 | 7 13 | mpteq12dv | |- ( w = W -> ( f e. ( LFnl ` w ) |-> ( `' f " { ( 0g ` ( Scalar ` w ) ) } ) ) = ( f e. F |-> ( `' f " { .0. } ) ) ) |
| 15 | df-lkr | |- LKer = ( w e. _V |-> ( f e. ( LFnl ` w ) |-> ( `' f " { ( 0g ` ( Scalar ` w ) ) } ) ) ) |
|
| 16 | 14 15 3 | mptfvmpt | |- ( W e. _V -> ( LKer ` W ) = ( f e. F |-> ( `' f " { .0. } ) ) ) |
| 17 | 4 16 | eqtrid | |- ( W e. _V -> K = ( f e. F |-> ( `' f " { .0. } ) ) ) |
| 18 | 5 17 | syl | |- ( W e. X -> K = ( f e. F |-> ( `' f " { .0. } ) ) ) |