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Description: Two ways to express restriction of range Cartesian product, see also xrnres , xrnres3 . (Contributed by Peter Mazsa, 6-Sep-2021)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | xrnres2 | ⊢ ( ( 𝑅 ⋉ 𝑆 ) ↾ 𝐴 ) = ( 𝑅 ⋉ ( 𝑆 ↾ 𝐴 ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | resco | ⊢ ( ( ◡ ( 2nd ↾ ( V × V ) ) ∘ 𝑆 ) ↾ 𝐴 ) = ( ◡ ( 2nd ↾ ( V × V ) ) ∘ ( 𝑆 ↾ 𝐴 ) ) | |
| 2 | 1 | ineq2i | ⊢ ( ( ◡ ( 1st ↾ ( V × V ) ) ∘ 𝑅 ) ∩ ( ( ◡ ( 2nd ↾ ( V × V ) ) ∘ 𝑆 ) ↾ 𝐴 ) ) = ( ( ◡ ( 1st ↾ ( V × V ) ) ∘ 𝑅 ) ∩ ( ◡ ( 2nd ↾ ( V × V ) ) ∘ ( 𝑆 ↾ 𝐴 ) ) ) |
| 3 | df-xrn | ⊢ ( 𝑅 ⋉ 𝑆 ) = ( ( ◡ ( 1st ↾ ( V × V ) ) ∘ 𝑅 ) ∩ ( ◡ ( 2nd ↾ ( V × V ) ) ∘ 𝑆 ) ) | |
| 4 | 3 | reseq1i | ⊢ ( ( 𝑅 ⋉ 𝑆 ) ↾ 𝐴 ) = ( ( ( ◡ ( 1st ↾ ( V × V ) ) ∘ 𝑅 ) ∩ ( ◡ ( 2nd ↾ ( V × V ) ) ∘ 𝑆 ) ) ↾ 𝐴 ) |
| 5 | inres | ⊢ ( ( ◡ ( 1st ↾ ( V × V ) ) ∘ 𝑅 ) ∩ ( ( ◡ ( 2nd ↾ ( V × V ) ) ∘ 𝑆 ) ↾ 𝐴 ) ) = ( ( ( ◡ ( 1st ↾ ( V × V ) ) ∘ 𝑅 ) ∩ ( ◡ ( 2nd ↾ ( V × V ) ) ∘ 𝑆 ) ) ↾ 𝐴 ) | |
| 6 | 4 5 | eqtr4i | ⊢ ( ( 𝑅 ⋉ 𝑆 ) ↾ 𝐴 ) = ( ( ◡ ( 1st ↾ ( V × V ) ) ∘ 𝑅 ) ∩ ( ( ◡ ( 2nd ↾ ( V × V ) ) ∘ 𝑆 ) ↾ 𝐴 ) ) |
| 7 | df-xrn | ⊢ ( 𝑅 ⋉ ( 𝑆 ↾ 𝐴 ) ) = ( ( ◡ ( 1st ↾ ( V × V ) ) ∘ 𝑅 ) ∩ ( ◡ ( 2nd ↾ ( V × V ) ) ∘ ( 𝑆 ↾ 𝐴 ) ) ) | |
| 8 | 2 6 7 | 3eqtr4i | ⊢ ( ( 𝑅 ⋉ 𝑆 ) ↾ 𝐴 ) = ( 𝑅 ⋉ ( 𝑆 ↾ 𝐴 ) ) |