Description: Membership in a class abstraction, using two substitution hypotheses to avoid a disjoint variable condition on x and A , which is not usually significant since B is usually a constant. (Contributed by SN, 16-May-2024)
Ref | Expression | ||
---|---|---|---|
Hypotheses | elabgw.1 | |
|
elabgw.2 | |
||
elab2gw.3 | |
||
Assertion | elab2gw | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | elabgw.1 | |
|
2 | elabgw.2 | |
|
3 | elab2gw.3 | |
|
4 | 3 | eleq2i | |
5 | 1 2 | elabgw | |
6 | 4 5 | syl5bb | |