Description: Class restriction distributes over intersection. (Contributed by NM, 18-Dec-2008)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | resindir | |- ( ( A i^i B ) |` C ) = ( ( A |` C ) i^i ( B |` C ) )  | 
				
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | inindir | |- ( ( A i^i B ) i^i ( C X. _V ) ) = ( ( A i^i ( C X. _V ) ) i^i ( B i^i ( C X. _V ) ) )  | 
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| 2 | df-res | |- ( ( A i^i B ) |` C ) = ( ( A i^i B ) i^i ( C X. _V ) )  | 
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| 3 | df-res | |- ( A |` C ) = ( A i^i ( C X. _V ) )  | 
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| 4 | df-res | |- ( B |` C ) = ( B i^i ( C X. _V ) )  | 
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| 5 | 3 4 | ineq12i | |- ( ( A |` C ) i^i ( B |` C ) ) = ( ( A i^i ( C X. _V ) ) i^i ( B i^i ( C X. _V ) ) )  | 
						
| 6 | 1 2 5 | 3eqtr4i | |- ( ( A i^i B ) |` C ) = ( ( A |` C ) i^i ( B |` C ) )  |