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Description: Lemma for 1stcrest . (Contributed by Mario Carneiro, 21-Mar-2015) (Revised by Mario Carneiro, 30-Apr-2015)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | 1stcrestlem | |- ( B ~<_ _om -> ran ( x e. B |-> C ) ~<_ _om ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ordom | |- Ord _om |
|
| 2 | reldom | |- Rel ~<_ |
|
| 3 | 2 | brrelex2i | |- ( B ~<_ _om -> _om e. _V ) |
| 4 | elong | |- ( _om e. _V -> ( _om e. On <-> Ord _om ) ) |
|
| 5 | 3 4 | syl | |- ( B ~<_ _om -> ( _om e. On <-> Ord _om ) ) |
| 6 | 1 5 | mpbiri | |- ( B ~<_ _om -> _om e. On ) |
| 7 | ondomen | |- ( ( _om e. On /\ B ~<_ _om ) -> B e. dom card ) |
|
| 8 | 6 7 | mpancom | |- ( B ~<_ _om -> B e. dom card ) |
| 9 | eqid | |- ( x e. B |-> C ) = ( x e. B |-> C ) |
|
| 10 | 9 | dmmptss | |- dom ( x e. B |-> C ) C_ B |
| 11 | ssnum | |- ( ( B e. dom card /\ dom ( x e. B |-> C ) C_ B ) -> dom ( x e. B |-> C ) e. dom card ) |
|
| 12 | 8 10 11 | sylancl | |- ( B ~<_ _om -> dom ( x e. B |-> C ) e. dom card ) |
| 13 | funmpt | |- Fun ( x e. B |-> C ) |
|
| 14 | funforn | |- ( Fun ( x e. B |-> C ) <-> ( x e. B |-> C ) : dom ( x e. B |-> C ) -onto-> ran ( x e. B |-> C ) ) |
|
| 15 | 13 14 | mpbi | |- ( x e. B |-> C ) : dom ( x e. B |-> C ) -onto-> ran ( x e. B |-> C ) |
| 16 | fodomnum | |- ( dom ( x e. B |-> C ) e. dom card -> ( ( x e. B |-> C ) : dom ( x e. B |-> C ) -onto-> ran ( x e. B |-> C ) -> ran ( x e. B |-> C ) ~<_ dom ( x e. B |-> C ) ) ) |
|
| 17 | 12 15 16 | mpisyl | |- ( B ~<_ _om -> ran ( x e. B |-> C ) ~<_ dom ( x e. B |-> C ) ) |
| 18 | ctex | |- ( B ~<_ _om -> B e. _V ) |
|
| 19 | ssdomg | |- ( B e. _V -> ( dom ( x e. B |-> C ) C_ B -> dom ( x e. B |-> C ) ~<_ B ) ) |
|
| 20 | 18 10 19 | mpisyl | |- ( B ~<_ _om -> dom ( x e. B |-> C ) ~<_ B ) |
| 21 | domtr | |- ( ( dom ( x e. B |-> C ) ~<_ B /\ B ~<_ _om ) -> dom ( x e. B |-> C ) ~<_ _om ) |
|
| 22 | 20 21 | mpancom | |- ( B ~<_ _om -> dom ( x e. B |-> C ) ~<_ _om ) |
| 23 | domtr | |- ( ( ran ( x e. B |-> C ) ~<_ dom ( x e. B |-> C ) /\ dom ( x e. B |-> C ) ~<_ _om ) -> ran ( x e. B |-> C ) ~<_ _om ) |
|
| 24 | 17 22 23 | syl2anc | |- ( B ~<_ _om -> ran ( x e. B |-> C ) ~<_ _om ) |