Description: Union of complementary parts into whole. (Contributed by Thierry Arnoux, 21-Nov-2023) (Proof shortened by SN, 11-Mar-2025)
Ref | Expression | ||
---|---|---|---|
Assertion | undifr | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ssequn2 | |
|
2 | undif1 | |
|
3 | 2 | eqeq1i | |
4 | 1 3 | bitr4i | |