Description: Equality theorem for the collection operation. (Contributed by Rohan Ridenour, 11-Aug-2023)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | colleq12d.1 | ||
| colleq12d.2 | |||
| Assertion | colleq12d |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | colleq12d.1 | ||
| 2 | colleq12d.2 | ||
| 3 | 1 | imaeq1d | |
| 4 | 3 | scotteqd | |
| 5 | 2 4 | iuneq12d | |
| 6 | df-coll | ||
| 7 | df-coll | ||
| 8 | 5 6 7 | 3eqtr4g |