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Description: The image of a compact set under a continuous function is compact. (Contributed by Mario Carneiro, 18-Feb-2015) (Revised by Mario Carneiro, 22-Aug-2015)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | imacmp | |- ( ( F e. ( J Cn K ) /\ ( J |`t A ) e. Comp ) -> ( K |`t ( F " A ) ) e. Comp ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | df-ima | |- ( F " A ) = ran ( F |` A ) |
|
| 2 | 1 | oveq2i | |- ( K |`t ( F " A ) ) = ( K |`t ran ( F |` A ) ) |
| 3 | simpr | |- ( ( F e. ( J Cn K ) /\ ( J |`t A ) e. Comp ) -> ( J |`t A ) e. Comp ) |
|
| 4 | simpl | |- ( ( F e. ( J Cn K ) /\ ( J |`t A ) e. Comp ) -> F e. ( J Cn K ) ) |
|
| 5 | inss2 | |- ( A i^i U. J ) C_ U. J |
|
| 6 | eqid | |- U. J = U. J |
|
| 7 | 6 | cnrest | |- ( ( F e. ( J Cn K ) /\ ( A i^i U. J ) C_ U. J ) -> ( F |` ( A i^i U. J ) ) e. ( ( J |`t ( A i^i U. J ) ) Cn K ) ) |
| 8 | 4 5 7 | sylancl | |- ( ( F e. ( J Cn K ) /\ ( J |`t A ) e. Comp ) -> ( F |` ( A i^i U. J ) ) e. ( ( J |`t ( A i^i U. J ) ) Cn K ) ) |
| 9 | resdmres | |- ( F |` dom ( F |` A ) ) = ( F |` A ) |
|
| 10 | dmres | |- dom ( F |` A ) = ( A i^i dom F ) |
|
| 11 | eqid | |- U. K = U. K |
|
| 12 | 6 11 | cnf | |- ( F e. ( J Cn K ) -> F : U. J --> U. K ) |
| 13 | fdm | |- ( F : U. J --> U. K -> dom F = U. J ) |
|
| 14 | 4 12 13 | 3syl | |- ( ( F e. ( J Cn K ) /\ ( J |`t A ) e. Comp ) -> dom F = U. J ) |
| 15 | 14 | ineq2d | |- ( ( F e. ( J Cn K ) /\ ( J |`t A ) e. Comp ) -> ( A i^i dom F ) = ( A i^i U. J ) ) |
| 16 | 10 15 | eqtrid | |- ( ( F e. ( J Cn K ) /\ ( J |`t A ) e. Comp ) -> dom ( F |` A ) = ( A i^i U. J ) ) |
| 17 | 16 | reseq2d | |- ( ( F e. ( J Cn K ) /\ ( J |`t A ) e. Comp ) -> ( F |` dom ( F |` A ) ) = ( F |` ( A i^i U. J ) ) ) |
| 18 | 9 17 | eqtr3id | |- ( ( F e. ( J Cn K ) /\ ( J |`t A ) e. Comp ) -> ( F |` A ) = ( F |` ( A i^i U. J ) ) ) |
| 19 | cmptop | |- ( ( J |`t A ) e. Comp -> ( J |`t A ) e. Top ) |
|
| 20 | 19 | adantl | |- ( ( F e. ( J Cn K ) /\ ( J |`t A ) e. Comp ) -> ( J |`t A ) e. Top ) |
| 21 | restrcl | |- ( ( J |`t A ) e. Top -> ( J e. _V /\ A e. _V ) ) |
|
| 22 | 6 | restin | |- ( ( J e. _V /\ A e. _V ) -> ( J |`t A ) = ( J |`t ( A i^i U. J ) ) ) |
| 23 | 20 21 22 | 3syl | |- ( ( F e. ( J Cn K ) /\ ( J |`t A ) e. Comp ) -> ( J |`t A ) = ( J |`t ( A i^i U. J ) ) ) |
| 24 | 23 | oveq1d | |- ( ( F e. ( J Cn K ) /\ ( J |`t A ) e. Comp ) -> ( ( J |`t A ) Cn K ) = ( ( J |`t ( A i^i U. J ) ) Cn K ) ) |
| 25 | 8 18 24 | 3eltr4d | |- ( ( F e. ( J Cn K ) /\ ( J |`t A ) e. Comp ) -> ( F |` A ) e. ( ( J |`t A ) Cn K ) ) |
| 26 | rncmp | |- ( ( ( J |`t A ) e. Comp /\ ( F |` A ) e. ( ( J |`t A ) Cn K ) ) -> ( K |`t ran ( F |` A ) ) e. Comp ) |
|
| 27 | 3 25 26 | syl2anc | |- ( ( F e. ( J Cn K ) /\ ( J |`t A ) e. Comp ) -> ( K |`t ran ( F |` A ) ) e. Comp ) |
| 28 | 2 27 | eqeltrid | |- ( ( F e. ( J Cn K ) /\ ( J |`t A ) e. Comp ) -> ( K |`t ( F " A ) ) e. Comp ) |