Description: iotaex without ax-10 , ax-11 , ax-12 . (Contributed by SN, 6-Nov-2024)
Ref | Expression | ||
---|---|---|---|
Assertion | sn-iotaex | |- ( iota x ph ) e. _V |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | sn-iotaval | |- ( { x | ph } = { y } -> ( iota x ph ) = y ) |
|
2 | vex | |- y e. _V |
|
3 | 1 2 | eqeltrdi | |- ( { x | ph } = { y } -> ( iota x ph ) e. _V ) |
4 | 3 | exlimiv | |- ( E. y { x | ph } = { y } -> ( iota x ph ) e. _V ) |
5 | sn-iotanul | |- ( -. E. y { x | ph } = { y } -> ( iota x ph ) = (/) ) |
|
6 | 0ex | |- (/) e. _V |
|
7 | 5 6 | eqeltrdi | |- ( -. E. y { x | ph } = { y } -> ( iota x ph ) e. _V ) |
8 | 4 7 | pm2.61i | |- ( iota x ph ) e. _V |