Description: The weak universe closure is a subset of any other weak universe containing the set. (Contributed by Mario Carneiro, 2-Jan-2017)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | wuncss | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | ssexg | ||
| 2 | 1 | ancoms | |
| 3 | wuncval | ||
| 4 | 2 3 | syl | |
| 5 | sseq2 | ||
| 6 | 5 | intminss | |
| 7 | 4 6 | eqsstrd |