Description: An instance of ax-11 proved without it. The converse may not be provable without ax-11 (since using alcomiw would require a DV on ph , x , which defeats the purpose). (Contributed by BJ, 22-Dec-2020) (Proof modification is discouraged.)
Ref | Expression | ||
---|---|---|---|
Assertion | bj-ssblem2 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | equequ1 | |
|
2 | equequ2 | |
|
3 | 2 | imbi1d | |
4 | 1 3 | imbi12d | |
5 | 4 | alcomiw | |