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 | 
|---|---|---|---|
| 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 ) )  | 
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| 2 | idinxpssinxp2 | |- ( ( _I i^i ( A X. A ) ) C_ ( R i^i ( A X. A ) ) <-> A. x e. A x R x )  | 
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| 3 | 1 2 | bitr3i | |- ( A. x e. A A. y e. A ( x = y -> x R y ) <-> A. x e. A x R x )  |