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Description: Reverse closure for isomorphism relations. (Contributed by Zhi Wang, 17-Nov-2025)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | isorcl.i | ⊢ 𝐼 = ( Iso ‘ 𝐶 ) | |
| isorcl.f | ⊢ ( 𝜑 → 𝐹 ∈ ( 𝑋 𝐼 𝑌 ) ) | ||
| isorcl2.b | ⊢ 𝐵 = ( Base ‘ 𝐶 ) | ||
| Assertion | isorcl2 | ⊢ ( 𝜑 → ( 𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵 ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | isorcl.i | ⊢ 𝐼 = ( Iso ‘ 𝐶 ) | |
| 2 | isorcl.f | ⊢ ( 𝜑 → 𝐹 ∈ ( 𝑋 𝐼 𝑌 ) ) | |
| 3 | isorcl2.b | ⊢ 𝐵 = ( Base ‘ 𝐶 ) | |
| 4 | eqid | ⊢ ( Inv ‘ 𝐶 ) = ( Inv ‘ 𝐶 ) | |
| 5 | 1 2 | isorcl | ⊢ ( 𝜑 → 𝐶 ∈ Cat ) |
| 6 | 3 4 5 1 | isofval2 | ⊢ ( 𝜑 → 𝐼 = ( 𝑥 ∈ 𝐵 , 𝑦 ∈ 𝐵 ↦ dom ( 𝑥 ( Inv ‘ 𝐶 ) 𝑦 ) ) ) |
| 7 | 6 | oveqd | ⊢ ( 𝜑 → ( 𝑋 𝐼 𝑌 ) = ( 𝑋 ( 𝑥 ∈ 𝐵 , 𝑦 ∈ 𝐵 ↦ dom ( 𝑥 ( Inv ‘ 𝐶 ) 𝑦 ) ) 𝑌 ) ) |
| 8 | 2 7 | eleqtrd | ⊢ ( 𝜑 → 𝐹 ∈ ( 𝑋 ( 𝑥 ∈ 𝐵 , 𝑦 ∈ 𝐵 ↦ dom ( 𝑥 ( Inv ‘ 𝐶 ) 𝑦 ) ) 𝑌 ) ) |
| 9 | eqid | ⊢ ( 𝑥 ∈ 𝐵 , 𝑦 ∈ 𝐵 ↦ dom ( 𝑥 ( Inv ‘ 𝐶 ) 𝑦 ) ) = ( 𝑥 ∈ 𝐵 , 𝑦 ∈ 𝐵 ↦ dom ( 𝑥 ( Inv ‘ 𝐶 ) 𝑦 ) ) | |
| 10 | 9 | elmpocl | ⊢ ( 𝐹 ∈ ( 𝑋 ( 𝑥 ∈ 𝐵 , 𝑦 ∈ 𝐵 ↦ dom ( 𝑥 ( Inv ‘ 𝐶 ) 𝑦 ) ) 𝑌 ) → ( 𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵 ) ) |
| 11 | 8 10 | syl | ⊢ ( 𝜑 → ( 𝑋 ∈ 𝐵 ∧ 𝑌 ∈ 𝐵 ) ) |