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Description: Sufficient condition for a restricted range Cartesian product to be a set. (Contributed by Peter Mazsa, 16-Dec-2020) (Revised by Peter Mazsa, 7-Sep-2021)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | xrnresex | |- ( ( A e. V /\ R e. W /\ ( S |` A ) e. X ) -> ( R |X. ( S |` A ) ) e. _V ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | xrnres3 | |- ( ( R |X. S ) |` A ) = ( ( R |` A ) |X. ( S |` A ) ) |
|
| 2 | xrnres2 | |- ( ( R |X. S ) |` A ) = ( R |X. ( S |` A ) ) |
|
| 3 | 1 2 | eqtr3i | |- ( ( R |` A ) |X. ( S |` A ) ) = ( R |X. ( S |` A ) ) |
| 4 | dfres4 | |- ( R |` A ) = ( R i^i ( A X. ran ( R |` A ) ) ) |
|
| 5 | dfres4 | |- ( S |` A ) = ( S i^i ( A X. ran ( S |` A ) ) ) |
|
| 6 | 4 5 | xrneq12i | |- ( ( R |` A ) |X. ( S |` A ) ) = ( ( R i^i ( A X. ran ( R |` A ) ) ) |X. ( S i^i ( A X. ran ( S |` A ) ) ) ) |
| 7 | simp1 | |- ( ( A e. V /\ R e. W /\ ( S |` A ) e. X ) -> A e. V ) |
|
| 8 | resexg | |- ( R e. W -> ( R |` A ) e. _V ) |
|
| 9 | rnexg | |- ( ( R |` A ) e. _V -> ran ( R |` A ) e. _V ) |
|
| 10 | 8 9 | syl | |- ( R e. W -> ran ( R |` A ) e. _V ) |
| 11 | 10 | 3ad2ant2 | |- ( ( A e. V /\ R e. W /\ ( S |` A ) e. X ) -> ran ( R |` A ) e. _V ) |
| 12 | rnexg | |- ( ( S |` A ) e. X -> ran ( S |` A ) e. _V ) |
|
| 13 | 12 | 3ad2ant3 | |- ( ( A e. V /\ R e. W /\ ( S |` A ) e. X ) -> ran ( S |` A ) e. _V ) |
| 14 | inxpxrn | |- ( ( R i^i ( A X. ran ( R |` A ) ) ) |X. ( S i^i ( A X. ran ( S |` A ) ) ) ) = ( ( R |X. S ) i^i ( A X. ( ran ( R |` A ) X. ran ( S |` A ) ) ) ) |
|
| 15 | xrninxpex | |- ( ( A e. V /\ ran ( R |` A ) e. _V /\ ran ( S |` A ) e. _V ) -> ( ( R |X. S ) i^i ( A X. ( ran ( R |` A ) X. ran ( S |` A ) ) ) ) e. _V ) |
|
| 16 | 14 15 | eqeltrid | |- ( ( A e. V /\ ran ( R |` A ) e. _V /\ ran ( S |` A ) e. _V ) -> ( ( R i^i ( A X. ran ( R |` A ) ) ) |X. ( S i^i ( A X. ran ( S |` A ) ) ) ) e. _V ) |
| 17 | 7 11 13 16 | syl3anc | |- ( ( A e. V /\ R e. W /\ ( S |` A ) e. X ) -> ( ( R i^i ( A X. ran ( R |` A ) ) ) |X. ( S i^i ( A X. ran ( S |` A ) ) ) ) e. _V ) |
| 18 | 6 17 | eqeltrid | |- ( ( A e. V /\ R e. W /\ ( S |` A ) e. X ) -> ( ( R |` A ) |X. ( S |` A ) ) e. _V ) |
| 19 | 3 18 | eqeltrrid | |- ( ( A e. V /\ R e. W /\ ( S |` A ) e. X ) -> ( R |X. ( S |` A ) ) e. _V ) |