Description: Membership in an indexed union, one way. (Contributed by JJ, 27-Jul-2021)
Ref | Expression | ||
---|---|---|---|
Hypothesis | eliuni.1 | |
|
Assertion | eliuni | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | eliuni.1 | |
|
2 | 1 | eleq2d | |
3 | 2 | rspcev | |
4 | eliun | |
|
5 | 3 4 | sylibr | |