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Description: Lemma for disjdmqseq , partim2 and petlem via disjdmqs , (general version of the former prtlem19 ). (Contributed by Peter Mazsa, 16-Sep-2021)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | disjlem19 |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | disjlem18 | ||
| 2 | 1 | elvd | |
| 3 | 2 | imp31 | |
| 4 | elecALTV | ||
| 5 | 4 | elvd | |
| 6 | 5 | ad2antrr | |
| 7 | 3 6 | bitr4d | |
| 8 | 7 | eqrdv | |
| 9 | 8 | exp31 |