Metamath Proof Explorer
Description: A weak universe is closed under restrictions. (Contributed by Mario
Carneiro, 12-Jan-2017)
|
|
Ref |
Expression |
|
Hypotheses |
wun0.1 |
|
|
|
wunop.2 |
|
|
Assertion |
wunres |
|
Proof
Step |
Hyp |
Ref |
Expression |
1 |
|
wun0.1 |
|
2 |
|
wunop.2 |
|
3 |
|
resss |
|
4 |
3
|
a1i |
|
5 |
1 2 4
|
wunss |
|