Description: The union of a collection of closed sets is a subset. (Contributed by Zhi Wang, 29-Sep-2024)
Ref | Expression | ||
---|---|---|---|
Assertion | mreuniss | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | uniss | |
|
2 | 1 | adantl | |
3 | mreuni | |
|
4 | 3 | adantr | |
5 | 2 4 | sseqtrd | |