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Description: Lemma for axprg . (Contributed by GG, 11-Mar-2026)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | axprglem | |- ( x = A -> E. z A. w ( ( w = A \/ w = B ) -> w e. z ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | iseqsetv-clel | |- ( E. y y = B <-> E. w w = B ) |
|
| 2 | ax-pr | |- E. z A. w ( ( w = x \/ w = y ) -> w e. z ) |
|
| 3 | eqtr3 | |- ( ( w = B /\ y = B ) -> w = y ) |
|
| 4 | 3 | expcom | |- ( y = B -> ( w = B -> w = y ) ) |
| 5 | 4 | orim2d | |- ( y = B -> ( ( w = x \/ w = B ) -> ( w = x \/ w = y ) ) ) |
| 6 | 5 | imim1d | |- ( y = B -> ( ( ( w = x \/ w = y ) -> w e. z ) -> ( ( w = x \/ w = B ) -> w e. z ) ) ) |
| 7 | 6 | alimdv | |- ( y = B -> ( A. w ( ( w = x \/ w = y ) -> w e. z ) -> A. w ( ( w = x \/ w = B ) -> w e. z ) ) ) |
| 8 | 7 | eximdv | |- ( y = B -> ( E. z A. w ( ( w = x \/ w = y ) -> w e. z ) -> E. z A. w ( ( w = x \/ w = B ) -> w e. z ) ) ) |
| 9 | 2 8 | mpi | |- ( y = B -> E. z A. w ( ( w = x \/ w = B ) -> w e. z ) ) |
| 10 | 9 | exlimiv | |- ( E. y y = B -> E. z A. w ( ( w = x \/ w = B ) -> w e. z ) ) |
| 11 | 1 10 | sylbir | |- ( E. w w = B -> E. z A. w ( ( w = x \/ w = B ) -> w e. z ) ) |
| 12 | ax-pr | |- E. z A. w ( ( w = x \/ w = x ) -> w e. z ) |
|
| 13 | alnex | |- ( A. w -. w = B <-> -. E. w w = B ) |
|
| 14 | orel2 | |- ( -. w = B -> ( ( w = x \/ w = B ) -> w = x ) ) |
|
| 15 | pm2.67-2 | |- ( ( ( w = x \/ w = x ) -> w e. z ) -> ( w = x -> w e. z ) ) |
|
| 16 | 14 15 | syl9 | |- ( -. w = B -> ( ( ( w = x \/ w = x ) -> w e. z ) -> ( ( w = x \/ w = B ) -> w e. z ) ) ) |
| 17 | 16 | al2imi | |- ( A. w -. w = B -> ( A. w ( ( w = x \/ w = x ) -> w e. z ) -> A. w ( ( w = x \/ w = B ) -> w e. z ) ) ) |
| 18 | 13 17 | sylbir | |- ( -. E. w w = B -> ( A. w ( ( w = x \/ w = x ) -> w e. z ) -> A. w ( ( w = x \/ w = B ) -> w e. z ) ) ) |
| 19 | 18 | eximdv | |- ( -. E. w w = B -> ( E. z A. w ( ( w = x \/ w = x ) -> w e. z ) -> E. z A. w ( ( w = x \/ w = B ) -> w e. z ) ) ) |
| 20 | 12 19 | mpi | |- ( -. E. w w = B -> E. z A. w ( ( w = x \/ w = B ) -> w e. z ) ) |
| 21 | 11 20 | pm2.61i | |- E. z A. w ( ( w = x \/ w = B ) -> w e. z ) |
| 22 | eqtr3 | |- ( ( w = A /\ x = A ) -> w = x ) |
|
| 23 | 22 | expcom | |- ( x = A -> ( w = A -> w = x ) ) |
| 24 | 23 | orim1d | |- ( x = A -> ( ( w = A \/ w = B ) -> ( w = x \/ w = B ) ) ) |
| 25 | 24 | imim1d | |- ( x = A -> ( ( ( w = x \/ w = B ) -> w e. z ) -> ( ( w = A \/ w = B ) -> w e. z ) ) ) |
| 26 | 25 | alimdv | |- ( x = A -> ( A. w ( ( w = x \/ w = B ) -> w e. z ) -> A. w ( ( w = A \/ w = B ) -> w e. z ) ) ) |
| 27 | 26 | eximdv | |- ( x = A -> ( E. z A. w ( ( w = x \/ w = B ) -> w e. z ) -> E. z A. w ( ( w = A \/ w = B ) -> w e. z ) ) ) |
| 28 | 21 27 | mpi | |- ( x = A -> E. z A. w ( ( w = A \/ w = B ) -> w e. z ) ) |