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Description: Change the index set to a subset in a finite sum. (Contributed by Mario Carneiro, 21-Apr-2014)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | sumss.1 | |- ( ph -> A C_ B ) |
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| sumss.2 | |- ( ( ph /\ k e. A ) -> C e. CC ) |
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| sumss.3 | |- ( ( ph /\ k e. ( B \ A ) ) -> C = 0 ) |
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| fsumss.4 | |- ( ph -> B e. Fin ) |
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| Assertion | fsumss | |- ( ph -> sum_ k e. A C = sum_ k e. B C ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | sumss.1 | |- ( ph -> A C_ B ) |
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| 2 | sumss.2 | |- ( ( ph /\ k e. A ) -> C e. CC ) |
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| 3 | sumss.3 | |- ( ( ph /\ k e. ( B \ A ) ) -> C = 0 ) |
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| 4 | fsumss.4 | |- ( ph -> B e. Fin ) |
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| 5 | 1 | adantr | |- ( ( ph /\ B = (/) ) -> A C_ B ) |
| 6 | 2 | adantlr | |- ( ( ( ph /\ B = (/) ) /\ k e. A ) -> C e. CC ) |
| 7 | 3 | adantlr | |- ( ( ( ph /\ B = (/) ) /\ k e. ( B \ A ) ) -> C = 0 ) |
| 8 | simpr | |- ( ( ph /\ B = (/) ) -> B = (/) ) |
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| 9 | 0ss | |- (/) C_ ( ZZ>= ` 0 ) |
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| 10 | 8 9 | eqsstrdi | |- ( ( ph /\ B = (/) ) -> B C_ ( ZZ>= ` 0 ) ) |
| 11 | 5 6 7 10 | sumss | |- ( ( ph /\ B = (/) ) -> sum_ k e. A C = sum_ k e. B C ) |
| 12 | 11 | ex | |- ( ph -> ( B = (/) -> sum_ k e. A C = sum_ k e. B C ) ) |
| 13 | cnvimass | |- ( `' f " A ) C_ dom f |
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| 14 | simprr | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) |
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| 15 | f1of | |- ( f : ( 1 ... ( # ` B ) ) -1-1-onto-> B -> f : ( 1 ... ( # ` B ) ) --> B ) |
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| 16 | 14 15 | syl | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> f : ( 1 ... ( # ` B ) ) --> B ) |
| 17 | 13 16 | fssdm | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> ( `' f " A ) C_ ( 1 ... ( # ` B ) ) ) |
| 18 | 16 | ffnd | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> f Fn ( 1 ... ( # ` B ) ) ) |
| 19 | elpreima | |- ( f Fn ( 1 ... ( # ` B ) ) -> ( n e. ( `' f " A ) <-> ( n e. ( 1 ... ( # ` B ) ) /\ ( f ` n ) e. A ) ) ) |
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| 20 | 18 19 | syl | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> ( n e. ( `' f " A ) <-> ( n e. ( 1 ... ( # ` B ) ) /\ ( f ` n ) e. A ) ) ) |
| 21 | 16 | ffvelcdmda | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ n e. ( 1 ... ( # ` B ) ) ) -> ( f ` n ) e. B ) |
| 22 | 21 | ex | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> ( n e. ( 1 ... ( # ` B ) ) -> ( f ` n ) e. B ) ) |
| 23 | 22 | adantrd | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> ( ( n e. ( 1 ... ( # ` B ) ) /\ ( f ` n ) e. A ) -> ( f ` n ) e. B ) ) |
| 24 | 20 23 | sylbid | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> ( n e. ( `' f " A ) -> ( f ` n ) e. B ) ) |
| 25 | 24 | imp | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ n e. ( `' f " A ) ) -> ( f ` n ) e. B ) |
| 26 | 2 | ex | |- ( ph -> ( k e. A -> C e. CC ) ) |
| 27 | 26 | adantr | |- ( ( ph /\ k e. B ) -> ( k e. A -> C e. CC ) ) |
| 28 | eldif | |- ( k e. ( B \ A ) <-> ( k e. B /\ -. k e. A ) ) |
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| 29 | 0cn | |- 0 e. CC |
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| 30 | 3 29 | eqeltrdi | |- ( ( ph /\ k e. ( B \ A ) ) -> C e. CC ) |
| 31 | 28 30 | sylan2br | |- ( ( ph /\ ( k e. B /\ -. k e. A ) ) -> C e. CC ) |
| 32 | 31 | expr | |- ( ( ph /\ k e. B ) -> ( -. k e. A -> C e. CC ) ) |
| 33 | 27 32 | pm2.61d | |- ( ( ph /\ k e. B ) -> C e. CC ) |
| 34 | 33 | fmpttd | |- ( ph -> ( k e. B |-> C ) : B --> CC ) |
| 35 | 34 | adantr | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> ( k e. B |-> C ) : B --> CC ) |
| 36 | 35 | ffvelcdmda | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ ( f ` n ) e. B ) -> ( ( k e. B |-> C ) ` ( f ` n ) ) e. CC ) |
| 37 | 25 36 | syldan | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ n e. ( `' f " A ) ) -> ( ( k e. B |-> C ) ` ( f ` n ) ) e. CC ) |
| 38 | eldifi | |- ( n e. ( ( 1 ... ( # ` B ) ) \ ( `' f " A ) ) -> n e. ( 1 ... ( # ` B ) ) ) |
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| 39 | 38 21 | sylan2 | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ n e. ( ( 1 ... ( # ` B ) ) \ ( `' f " A ) ) ) -> ( f ` n ) e. B ) |
| 40 | eldifn | |- ( n e. ( ( 1 ... ( # ` B ) ) \ ( `' f " A ) ) -> -. n e. ( `' f " A ) ) |
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| 41 | 40 | adantl | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ n e. ( ( 1 ... ( # ` B ) ) \ ( `' f " A ) ) ) -> -. n e. ( `' f " A ) ) |
| 42 | 38 | adantl | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ n e. ( ( 1 ... ( # ` B ) ) \ ( `' f " A ) ) ) -> n e. ( 1 ... ( # ` B ) ) ) |
| 43 | 20 | adantr | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ n e. ( ( 1 ... ( # ` B ) ) \ ( `' f " A ) ) ) -> ( n e. ( `' f " A ) <-> ( n e. ( 1 ... ( # ` B ) ) /\ ( f ` n ) e. A ) ) ) |
| 44 | 42 43 | mpbirand | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ n e. ( ( 1 ... ( # ` B ) ) \ ( `' f " A ) ) ) -> ( n e. ( `' f " A ) <-> ( f ` n ) e. A ) ) |
| 45 | 41 44 | mtbid | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ n e. ( ( 1 ... ( # ` B ) ) \ ( `' f " A ) ) ) -> -. ( f ` n ) e. A ) |
| 46 | 39 45 | eldifd | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ n e. ( ( 1 ... ( # ` B ) ) \ ( `' f " A ) ) ) -> ( f ` n ) e. ( B \ A ) ) |
| 47 | difss | |- ( B \ A ) C_ B |
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| 48 | resmpt | |- ( ( B \ A ) C_ B -> ( ( k e. B |-> C ) |` ( B \ A ) ) = ( k e. ( B \ A ) |-> C ) ) |
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| 49 | 47 48 | ax-mp | |- ( ( k e. B |-> C ) |` ( B \ A ) ) = ( k e. ( B \ A ) |-> C ) |
| 50 | 49 | fveq1i | |- ( ( ( k e. B |-> C ) |` ( B \ A ) ) ` ( f ` n ) ) = ( ( k e. ( B \ A ) |-> C ) ` ( f ` n ) ) |
| 51 | fvres | |- ( ( f ` n ) e. ( B \ A ) -> ( ( ( k e. B |-> C ) |` ( B \ A ) ) ` ( f ` n ) ) = ( ( k e. B |-> C ) ` ( f ` n ) ) ) |
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| 52 | 50 51 | eqtr3id | |- ( ( f ` n ) e. ( B \ A ) -> ( ( k e. ( B \ A ) |-> C ) ` ( f ` n ) ) = ( ( k e. B |-> C ) ` ( f ` n ) ) ) |
| 53 | 46 52 | syl | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ n e. ( ( 1 ... ( # ` B ) ) \ ( `' f " A ) ) ) -> ( ( k e. ( B \ A ) |-> C ) ` ( f ` n ) ) = ( ( k e. B |-> C ) ` ( f ` n ) ) ) |
| 54 | c0ex | |- 0 e. _V |
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| 55 | 54 | elsn2 | |- ( C e. { 0 } <-> C = 0 ) |
| 56 | 3 55 | sylibr | |- ( ( ph /\ k e. ( B \ A ) ) -> C e. { 0 } ) |
| 57 | 56 | fmpttd | |- ( ph -> ( k e. ( B \ A ) |-> C ) : ( B \ A ) --> { 0 } ) |
| 58 | 57 | ad2antrr | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ n e. ( ( 1 ... ( # ` B ) ) \ ( `' f " A ) ) ) -> ( k e. ( B \ A ) |-> C ) : ( B \ A ) --> { 0 } ) |
| 59 | 58 46 | ffvelcdmd | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ n e. ( ( 1 ... ( # ` B ) ) \ ( `' f " A ) ) ) -> ( ( k e. ( B \ A ) |-> C ) ` ( f ` n ) ) e. { 0 } ) |
| 60 | elsni | |- ( ( ( k e. ( B \ A ) |-> C ) ` ( f ` n ) ) e. { 0 } -> ( ( k e. ( B \ A ) |-> C ) ` ( f ` n ) ) = 0 ) |
|
| 61 | 59 60 | syl | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ n e. ( ( 1 ... ( # ` B ) ) \ ( `' f " A ) ) ) -> ( ( k e. ( B \ A ) |-> C ) ` ( f ` n ) ) = 0 ) |
| 62 | 53 61 | eqtr3d | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ n e. ( ( 1 ... ( # ` B ) ) \ ( `' f " A ) ) ) -> ( ( k e. B |-> C ) ` ( f ` n ) ) = 0 ) |
| 63 | fzssuz | |- ( 1 ... ( # ` B ) ) C_ ( ZZ>= ` 1 ) |
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| 64 | 63 | a1i | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> ( 1 ... ( # ` B ) ) C_ ( ZZ>= ` 1 ) ) |
| 65 | 17 37 62 64 | sumss | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> sum_ n e. ( `' f " A ) ( ( k e. B |-> C ) ` ( f ` n ) ) = sum_ n e. ( 1 ... ( # ` B ) ) ( ( k e. B |-> C ) ` ( f ` n ) ) ) |
| 66 | 1 | ad2antrr | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ m e. A ) -> A C_ B ) |
| 67 | 66 | resmptd | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ m e. A ) -> ( ( k e. B |-> C ) |` A ) = ( k e. A |-> C ) ) |
| 68 | 67 | fveq1d | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ m e. A ) -> ( ( ( k e. B |-> C ) |` A ) ` m ) = ( ( k e. A |-> C ) ` m ) ) |
| 69 | fvres | |- ( m e. A -> ( ( ( k e. B |-> C ) |` A ) ` m ) = ( ( k e. B |-> C ) ` m ) ) |
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| 70 | 69 | adantl | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ m e. A ) -> ( ( ( k e. B |-> C ) |` A ) ` m ) = ( ( k e. B |-> C ) ` m ) ) |
| 71 | 68 70 | eqtr3d | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ m e. A ) -> ( ( k e. A |-> C ) ` m ) = ( ( k e. B |-> C ) ` m ) ) |
| 72 | 71 | sumeq2dv | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> sum_ m e. A ( ( k e. A |-> C ) ` m ) = sum_ m e. A ( ( k e. B |-> C ) ` m ) ) |
| 73 | fveq2 | |- ( m = ( f ` n ) -> ( ( k e. B |-> C ) ` m ) = ( ( k e. B |-> C ) ` ( f ` n ) ) ) |
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| 74 | fzfid | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> ( 1 ... ( # ` B ) ) e. Fin ) |
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| 75 | 74 16 | fisuppfi | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> ( `' f " A ) e. Fin ) |
| 76 | f1of1 | |- ( f : ( 1 ... ( # ` B ) ) -1-1-onto-> B -> f : ( 1 ... ( # ` B ) ) -1-1-> B ) |
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| 77 | 14 76 | syl | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> f : ( 1 ... ( # ` B ) ) -1-1-> B ) |
| 78 | f1ores | |- ( ( f : ( 1 ... ( # ` B ) ) -1-1-> B /\ ( `' f " A ) C_ ( 1 ... ( # ` B ) ) ) -> ( f |` ( `' f " A ) ) : ( `' f " A ) -1-1-onto-> ( f " ( `' f " A ) ) ) |
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| 79 | 77 17 78 | syl2anc | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> ( f |` ( `' f " A ) ) : ( `' f " A ) -1-1-onto-> ( f " ( `' f " A ) ) ) |
| 80 | f1ofo | |- ( f : ( 1 ... ( # ` B ) ) -1-1-onto-> B -> f : ( 1 ... ( # ` B ) ) -onto-> B ) |
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| 81 | 14 80 | syl | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> f : ( 1 ... ( # ` B ) ) -onto-> B ) |
| 82 | 1 | adantr | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> A C_ B ) |
| 83 | foimacnv | |- ( ( f : ( 1 ... ( # ` B ) ) -onto-> B /\ A C_ B ) -> ( f " ( `' f " A ) ) = A ) |
|
| 84 | 81 82 83 | syl2anc | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> ( f " ( `' f " A ) ) = A ) |
| 85 | 84 | f1oeq3d | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> ( ( f |` ( `' f " A ) ) : ( `' f " A ) -1-1-onto-> ( f " ( `' f " A ) ) <-> ( f |` ( `' f " A ) ) : ( `' f " A ) -1-1-onto-> A ) ) |
| 86 | 79 85 | mpbid | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> ( f |` ( `' f " A ) ) : ( `' f " A ) -1-1-onto-> A ) |
| 87 | fvres | |- ( n e. ( `' f " A ) -> ( ( f |` ( `' f " A ) ) ` n ) = ( f ` n ) ) |
|
| 88 | 87 | adantl | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ n e. ( `' f " A ) ) -> ( ( f |` ( `' f " A ) ) ` n ) = ( f ` n ) ) |
| 89 | 82 | sselda | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ m e. A ) -> m e. B ) |
| 90 | 35 | ffvelcdmda | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ m e. B ) -> ( ( k e. B |-> C ) ` m ) e. CC ) |
| 91 | 89 90 | syldan | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ m e. A ) -> ( ( k e. B |-> C ) ` m ) e. CC ) |
| 92 | 73 75 86 88 91 | fsumf1o | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> sum_ m e. A ( ( k e. B |-> C ) ` m ) = sum_ n e. ( `' f " A ) ( ( k e. B |-> C ) ` ( f ` n ) ) ) |
| 93 | 72 92 | eqtrd | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> sum_ m e. A ( ( k e. A |-> C ) ` m ) = sum_ n e. ( `' f " A ) ( ( k e. B |-> C ) ` ( f ` n ) ) ) |
| 94 | eqidd | |- ( ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) /\ n e. ( 1 ... ( # ` B ) ) ) -> ( f ` n ) = ( f ` n ) ) |
|
| 95 | 73 74 14 94 90 | fsumf1o | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> sum_ m e. B ( ( k e. B |-> C ) ` m ) = sum_ n e. ( 1 ... ( # ` B ) ) ( ( k e. B |-> C ) ` ( f ` n ) ) ) |
| 96 | 65 93 95 | 3eqtr4d | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> sum_ m e. A ( ( k e. A |-> C ) ` m ) = sum_ m e. B ( ( k e. B |-> C ) ` m ) ) |
| 97 | sumfc | |- sum_ m e. A ( ( k e. A |-> C ) ` m ) = sum_ k e. A C |
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| 98 | sumfc | |- sum_ m e. B ( ( k e. B |-> C ) ` m ) = sum_ k e. B C |
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| 99 | 96 97 98 | 3eqtr3g | |- ( ( ph /\ ( ( # ` B ) e. NN /\ f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) -> sum_ k e. A C = sum_ k e. B C ) |
| 100 | 99 | expr | |- ( ( ph /\ ( # ` B ) e. NN ) -> ( f : ( 1 ... ( # ` B ) ) -1-1-onto-> B -> sum_ k e. A C = sum_ k e. B C ) ) |
| 101 | 100 | exlimdv | |- ( ( ph /\ ( # ` B ) e. NN ) -> ( E. f f : ( 1 ... ( # ` B ) ) -1-1-onto-> B -> sum_ k e. A C = sum_ k e. B C ) ) |
| 102 | 101 | expimpd | |- ( ph -> ( ( ( # ` B ) e. NN /\ E. f f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) -> sum_ k e. A C = sum_ k e. B C ) ) |
| 103 | fz1f1o | |- ( B e. Fin -> ( B = (/) \/ ( ( # ` B ) e. NN /\ E. f f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) ) |
|
| 104 | 4 103 | syl | |- ( ph -> ( B = (/) \/ ( ( # ` B ) e. NN /\ E. f f : ( 1 ... ( # ` B ) ) -1-1-onto-> B ) ) ) |
| 105 | 12 102 104 | mpjaod | |- ( ph -> sum_ k e. A C = sum_ k e. B C ) |