Description: Identity intersection with a square Cartesian product in subclass relation with an intersection with the same Cartesian product (see also idinxpssinxp2 ). (Contributed by Peter Mazsa, 8-Mar-2019)
Ref | Expression | ||
---|---|---|---|
Assertion | idinxpssinxp4 | |- ( A. x e. A A. y e. A ( x = y -> x R y ) <-> A. x e. A x R x ) |
Step | Hyp | Ref | Expression |
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1 | idinxpssinxp | |- ( ( _I i^i ( A X. A ) ) C_ ( R i^i ( A X. A ) ) <-> A. x e. A A. y e. A ( x = y -> x R y ) ) |
|
2 | idinxpssinxp2 | |- ( ( _I i^i ( A X. A ) ) C_ ( R i^i ( A X. A ) ) <-> A. x e. A x R x ) |
|
3 | 1 2 | bitr3i | |- ( A. x e. A A. y e. A ( x = y -> x R y ) <-> A. x e. A x R x ) |