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Description: Identity intersection with a square Cartesian product in subclass relation with an intersection with the same Cartesian product. (Contributed by Peter Mazsa, 4-Mar-2019) (Proof modification is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | idinxpssinxp2 |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | idinxpresid | ||
| 2 | 1 | sseq1i | |
| 3 | idrefALT | ||
| 4 | brinxp2 | ||
| 5 | pm4.24 | ||
| 6 | 5 | anbi1i | |
| 7 | 4 6 | bitr4i | |
| 8 | 7 | ralbii | |
| 9 | 2 3 8 | 3bitri | |
| 10 | ralanid | ||
| 11 | 9 10 | bitri |