Description: Lemma for bj-ax6e . (Contributed by BJ, 22-Dec-2020) (Proof modification is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | bj-ax6elem2 | |- ( A. x y = z -> E. x x = y ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ax6ev | |- E. x x = z |
|
| 2 | equeucl | |- ( x = z -> ( y = z -> x = y ) ) |
|
| 3 | 1 2 | eximii | |- E. x ( y = z -> x = y ) |
| 4 | 3 | 19.35i | |- ( A. x y = z -> E. x x = y ) |