Description: Appending a set to an indexed union. (Contributed by Thierry Arnoux, 20-Nov-2023)
Ref | Expression | ||
---|---|---|---|
Hypothesis | iunxunsn.1 | ||
Assertion | iunxunsn |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | iunxunsn.1 | ||
2 | iunxun | ||
3 | 1 | iunxsng | |
4 | 3 | uneq2d | |
5 | 2 4 | syl5eq |