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Description: The restriction of a one-to-one onto function to an intersection maps onto the intersection of the images. (Contributed by Paul Chapman, 11-Apr-2009)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | resin | ⊢ ( ( Fun ◡ 𝐹 ∧ ( 𝐹 ↾ 𝐴 ) : 𝐴 –onto→ 𝐶 ∧ ( 𝐹 ↾ 𝐵 ) : 𝐵 –onto→ 𝐷 ) → ( 𝐹 ↾ ( 𝐴 ∩ 𝐵 ) ) : ( 𝐴 ∩ 𝐵 ) –1-1-onto→ ( 𝐶 ∩ 𝐷 ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | resdif | ⊢ ( ( Fun ◡ 𝐹 ∧ ( 𝐹 ↾ 𝐴 ) : 𝐴 –onto→ 𝐶 ∧ ( 𝐹 ↾ 𝐵 ) : 𝐵 –onto→ 𝐷 ) → ( 𝐹 ↾ ( 𝐴 ∖ 𝐵 ) ) : ( 𝐴 ∖ 𝐵 ) –1-1-onto→ ( 𝐶 ∖ 𝐷 ) ) | |
| 2 | f1ofo | ⊢ ( ( 𝐹 ↾ ( 𝐴 ∖ 𝐵 ) ) : ( 𝐴 ∖ 𝐵 ) –1-1-onto→ ( 𝐶 ∖ 𝐷 ) → ( 𝐹 ↾ ( 𝐴 ∖ 𝐵 ) ) : ( 𝐴 ∖ 𝐵 ) –onto→ ( 𝐶 ∖ 𝐷 ) ) | |
| 3 | 1 2 | syl | ⊢ ( ( Fun ◡ 𝐹 ∧ ( 𝐹 ↾ 𝐴 ) : 𝐴 –onto→ 𝐶 ∧ ( 𝐹 ↾ 𝐵 ) : 𝐵 –onto→ 𝐷 ) → ( 𝐹 ↾ ( 𝐴 ∖ 𝐵 ) ) : ( 𝐴 ∖ 𝐵 ) –onto→ ( 𝐶 ∖ 𝐷 ) ) |
| 4 | resdif | ⊢ ( ( Fun ◡ 𝐹 ∧ ( 𝐹 ↾ 𝐴 ) : 𝐴 –onto→ 𝐶 ∧ ( 𝐹 ↾ ( 𝐴 ∖ 𝐵 ) ) : ( 𝐴 ∖ 𝐵 ) –onto→ ( 𝐶 ∖ 𝐷 ) ) → ( 𝐹 ↾ ( 𝐴 ∖ ( 𝐴 ∖ 𝐵 ) ) ) : ( 𝐴 ∖ ( 𝐴 ∖ 𝐵 ) ) –1-1-onto→ ( 𝐶 ∖ ( 𝐶 ∖ 𝐷 ) ) ) | |
| 5 | 3 4 | syld3an3 | ⊢ ( ( Fun ◡ 𝐹 ∧ ( 𝐹 ↾ 𝐴 ) : 𝐴 –onto→ 𝐶 ∧ ( 𝐹 ↾ 𝐵 ) : 𝐵 –onto→ 𝐷 ) → ( 𝐹 ↾ ( 𝐴 ∖ ( 𝐴 ∖ 𝐵 ) ) ) : ( 𝐴 ∖ ( 𝐴 ∖ 𝐵 ) ) –1-1-onto→ ( 𝐶 ∖ ( 𝐶 ∖ 𝐷 ) ) ) |
| 6 | dfin4 | ⊢ ( 𝐶 ∩ 𝐷 ) = ( 𝐶 ∖ ( 𝐶 ∖ 𝐷 ) ) | |
| 7 | f1oeq3 | ⊢ ( ( 𝐶 ∩ 𝐷 ) = ( 𝐶 ∖ ( 𝐶 ∖ 𝐷 ) ) → ( ( 𝐹 ↾ ( 𝐴 ∩ 𝐵 ) ) : ( 𝐴 ∩ 𝐵 ) –1-1-onto→ ( 𝐶 ∩ 𝐷 ) ↔ ( 𝐹 ↾ ( 𝐴 ∩ 𝐵 ) ) : ( 𝐴 ∩ 𝐵 ) –1-1-onto→ ( 𝐶 ∖ ( 𝐶 ∖ 𝐷 ) ) ) ) | |
| 8 | 6 7 | ax-mp | ⊢ ( ( 𝐹 ↾ ( 𝐴 ∩ 𝐵 ) ) : ( 𝐴 ∩ 𝐵 ) –1-1-onto→ ( 𝐶 ∩ 𝐷 ) ↔ ( 𝐹 ↾ ( 𝐴 ∩ 𝐵 ) ) : ( 𝐴 ∩ 𝐵 ) –1-1-onto→ ( 𝐶 ∖ ( 𝐶 ∖ 𝐷 ) ) ) |
| 9 | dfin4 | ⊢ ( 𝐴 ∩ 𝐵 ) = ( 𝐴 ∖ ( 𝐴 ∖ 𝐵 ) ) | |
| 10 | f1oeq2 | ⊢ ( ( 𝐴 ∩ 𝐵 ) = ( 𝐴 ∖ ( 𝐴 ∖ 𝐵 ) ) → ( ( 𝐹 ↾ ( 𝐴 ∩ 𝐵 ) ) : ( 𝐴 ∩ 𝐵 ) –1-1-onto→ ( 𝐶 ∖ ( 𝐶 ∖ 𝐷 ) ) ↔ ( 𝐹 ↾ ( 𝐴 ∩ 𝐵 ) ) : ( 𝐴 ∖ ( 𝐴 ∖ 𝐵 ) ) –1-1-onto→ ( 𝐶 ∖ ( 𝐶 ∖ 𝐷 ) ) ) ) | |
| 11 | 9 10 | ax-mp | ⊢ ( ( 𝐹 ↾ ( 𝐴 ∩ 𝐵 ) ) : ( 𝐴 ∩ 𝐵 ) –1-1-onto→ ( 𝐶 ∖ ( 𝐶 ∖ 𝐷 ) ) ↔ ( 𝐹 ↾ ( 𝐴 ∩ 𝐵 ) ) : ( 𝐴 ∖ ( 𝐴 ∖ 𝐵 ) ) –1-1-onto→ ( 𝐶 ∖ ( 𝐶 ∖ 𝐷 ) ) ) |
| 12 | 9 | reseq2i | ⊢ ( 𝐹 ↾ ( 𝐴 ∩ 𝐵 ) ) = ( 𝐹 ↾ ( 𝐴 ∖ ( 𝐴 ∖ 𝐵 ) ) ) |
| 13 | f1oeq1 | ⊢ ( ( 𝐹 ↾ ( 𝐴 ∩ 𝐵 ) ) = ( 𝐹 ↾ ( 𝐴 ∖ ( 𝐴 ∖ 𝐵 ) ) ) → ( ( 𝐹 ↾ ( 𝐴 ∩ 𝐵 ) ) : ( 𝐴 ∖ ( 𝐴 ∖ 𝐵 ) ) –1-1-onto→ ( 𝐶 ∖ ( 𝐶 ∖ 𝐷 ) ) ↔ ( 𝐹 ↾ ( 𝐴 ∖ ( 𝐴 ∖ 𝐵 ) ) ) : ( 𝐴 ∖ ( 𝐴 ∖ 𝐵 ) ) –1-1-onto→ ( 𝐶 ∖ ( 𝐶 ∖ 𝐷 ) ) ) ) | |
| 14 | 12 13 | ax-mp | ⊢ ( ( 𝐹 ↾ ( 𝐴 ∩ 𝐵 ) ) : ( 𝐴 ∖ ( 𝐴 ∖ 𝐵 ) ) –1-1-onto→ ( 𝐶 ∖ ( 𝐶 ∖ 𝐷 ) ) ↔ ( 𝐹 ↾ ( 𝐴 ∖ ( 𝐴 ∖ 𝐵 ) ) ) : ( 𝐴 ∖ ( 𝐴 ∖ 𝐵 ) ) –1-1-onto→ ( 𝐶 ∖ ( 𝐶 ∖ 𝐷 ) ) ) |
| 15 | 8 11 14 | 3bitrri | ⊢ ( ( 𝐹 ↾ ( 𝐴 ∖ ( 𝐴 ∖ 𝐵 ) ) ) : ( 𝐴 ∖ ( 𝐴 ∖ 𝐵 ) ) –1-1-onto→ ( 𝐶 ∖ ( 𝐶 ∖ 𝐷 ) ) ↔ ( 𝐹 ↾ ( 𝐴 ∩ 𝐵 ) ) : ( 𝐴 ∩ 𝐵 ) –1-1-onto→ ( 𝐶 ∩ 𝐷 ) ) |
| 16 | 5 15 | sylib | ⊢ ( ( Fun ◡ 𝐹 ∧ ( 𝐹 ↾ 𝐴 ) : 𝐴 –onto→ 𝐶 ∧ ( 𝐹 ↾ 𝐵 ) : 𝐵 –onto→ 𝐷 ) → ( 𝐹 ↾ ( 𝐴 ∩ 𝐵 ) ) : ( 𝐴 ∩ 𝐵 ) –1-1-onto→ ( 𝐶 ∩ 𝐷 ) ) |