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Description: Lemma for imasubc . (Contributed by Zhi Wang, 7-Nov-2025)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | imasubclem1.f | |- ( ph -> F e. V ) |
|
| imasubclem1.g | |- ( ph -> G e. W ) |
||
| imasubclem3.x | |- ( ph -> X e. A ) |
||
| imasubclem3.y | |- ( ph -> Y e. B ) |
||
| imasubclem3.k | |- K = ( x e. A , y e. B |-> U_ z e. ( ( `' F " { x } ) X. ( `' G " { y } ) ) ( ( H ` C ) " D ) ) |
||
| Assertion | imasubclem3 | |- ( ph -> ( X K Y ) = U_ z e. ( ( `' F " { X } ) X. ( `' G " { Y } ) ) ( ( H ` C ) " D ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | imasubclem1.f | |- ( ph -> F e. V ) |
|
| 2 | imasubclem1.g | |- ( ph -> G e. W ) |
|
| 3 | imasubclem3.x | |- ( ph -> X e. A ) |
|
| 4 | imasubclem3.y | |- ( ph -> Y e. B ) |
|
| 5 | imasubclem3.k | |- K = ( x e. A , y e. B |-> U_ z e. ( ( `' F " { x } ) X. ( `' G " { y } ) ) ( ( H ` C ) " D ) ) |
|
| 6 | 1 2 | imasubclem1 | |- ( ph -> U_ z e. ( ( `' F " { X } ) X. ( `' G " { Y } ) ) ( ( H ` C ) " D ) e. _V ) |
| 7 | simpl | |- ( ( x = X /\ y = Y ) -> x = X ) |
|
| 8 | 7 | sneqd | |- ( ( x = X /\ y = Y ) -> { x } = { X } ) |
| 9 | 8 | imaeq2d | |- ( ( x = X /\ y = Y ) -> ( `' F " { x } ) = ( `' F " { X } ) ) |
| 10 | simpr | |- ( ( x = X /\ y = Y ) -> y = Y ) |
|
| 11 | 10 | sneqd | |- ( ( x = X /\ y = Y ) -> { y } = { Y } ) |
| 12 | 11 | imaeq2d | |- ( ( x = X /\ y = Y ) -> ( `' G " { y } ) = ( `' G " { Y } ) ) |
| 13 | 9 12 | xpeq12d | |- ( ( x = X /\ y = Y ) -> ( ( `' F " { x } ) X. ( `' G " { y } ) ) = ( ( `' F " { X } ) X. ( `' G " { Y } ) ) ) |
| 14 | 13 | iuneq1d | |- ( ( x = X /\ y = Y ) -> U_ z e. ( ( `' F " { x } ) X. ( `' G " { y } ) ) ( ( H ` C ) " D ) = U_ z e. ( ( `' F " { X } ) X. ( `' G " { Y } ) ) ( ( H ` C ) " D ) ) |
| 15 | 14 5 | ovmpoga | |- ( ( X e. A /\ Y e. B /\ U_ z e. ( ( `' F " { X } ) X. ( `' G " { Y } ) ) ( ( H ` C ) " D ) e. _V ) -> ( X K Y ) = U_ z e. ( ( `' F " { X } ) X. ( `' G " { Y } ) ) ( ( H ` C ) " D ) ) |
| 16 | 3 4 6 15 | syl3anc | |- ( ph -> ( X K Y ) = U_ z e. ( ( `' F " { X } ) X. ( `' G " { Y } ) ) ( ( H ` C ) " D ) ) |