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Description: Identity intersection with a square Cartesian product in subclass relation with an intersection with the same Cartesian product. (Contributed by Peter Mazsa, 16-Mar-2019) (Proof modification is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | idinxpssinxp3 | ⊢ ( ( I ∩ ( 𝐴 × 𝐴 ) ) ⊆ ( 𝑅 ∩ ( 𝐴 × 𝐴 ) ) ↔ ( I ↾ 𝐴 ) ⊆ 𝑅 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | idinxpssinxp2 | ⊢ ( ( I ∩ ( 𝐴 × 𝐴 ) ) ⊆ ( 𝑅 ∩ ( 𝐴 × 𝐴 ) ) ↔ ∀ 𝑥 ∈ 𝐴 𝑥 𝑅 𝑥 ) | |
| 2 | idrefALT | ⊢ ( ( I ↾ 𝐴 ) ⊆ 𝑅 ↔ ∀ 𝑥 ∈ 𝐴 𝑥 𝑅 𝑥 ) | |
| 3 | 1 2 | bitr4i | ⊢ ( ( I ∩ ( 𝐴 × 𝐴 ) ) ⊆ ( 𝑅 ∩ ( 𝐴 × 𝐴 ) ) ↔ ( I ↾ 𝐴 ) ⊆ 𝑅 ) |