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Description: Disjointness condition for range Cartesian product. (Contributed by Peter Mazsa, 12-Jul-2020) (Revised by Peter Mazsa, 22-Sep-2021)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | disjorimxrn | |- ( ( Disj R \/ Disj S ) -> Disj ( R |X. S ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | dfdisjALTV2 | |- ( Disj R <-> ( ,~ `' R C_ _I /\ Rel R ) ) |
|
| 2 | 1 | simplbi | |- ( Disj R -> ,~ `' R C_ _I ) |
| 3 | dfdisjALTV2 | |- ( Disj S <-> ( ,~ `' S C_ _I /\ Rel S ) ) |
|
| 4 | 3 | simplbi | |- ( Disj S -> ,~ `' S C_ _I ) |
| 5 | 2 4 | orim12i | |- ( ( Disj R \/ Disj S ) -> ( ,~ `' R C_ _I \/ ,~ `' S C_ _I ) ) |
| 6 | inss | |- ( ( ,~ `' R C_ _I \/ ,~ `' S C_ _I ) -> ( ,~ `' R i^i ,~ `' S ) C_ _I ) |
|
| 7 | 5 6 | syl | |- ( ( Disj R \/ Disj S ) -> ( ,~ `' R i^i ,~ `' S ) C_ _I ) |
| 8 | disjxrn | |- ( Disj ( R |X. S ) <-> ( ,~ `' R i^i ,~ `' S ) C_ _I ) |
|
| 9 | 7 8 | sylibr | |- ( ( Disj R \/ Disj S ) -> Disj ( R |X. S ) ) |