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Description: Transfer a right identity law to the function operation. (Contributed by NM, 21-Oct-2014)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | caofref.1 | ⊢ ( 𝜑 → 𝐴 ∈ 𝑉 ) | |
| caofref.2 | ⊢ ( 𝜑 → 𝐹 : 𝐴 ⟶ 𝑆 ) | ||
| caofid0.3 | ⊢ ( 𝜑 → 𝐵 ∈ 𝑊 ) | ||
| caofid0r.5 | ⊢ ( ( 𝜑 ∧ 𝑥 ∈ 𝑆 ) → ( 𝑥 𝑅 𝐵 ) = 𝑥 ) | ||
| Assertion | caofid0r | ⊢ ( 𝜑 → ( 𝐹 ∘f 𝑅 ( 𝐴 × { 𝐵 } ) ) = 𝐹 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | caofref.1 | ⊢ ( 𝜑 → 𝐴 ∈ 𝑉 ) | |
| 2 | caofref.2 | ⊢ ( 𝜑 → 𝐹 : 𝐴 ⟶ 𝑆 ) | |
| 3 | caofid0.3 | ⊢ ( 𝜑 → 𝐵 ∈ 𝑊 ) | |
| 4 | caofid0r.5 | ⊢ ( ( 𝜑 ∧ 𝑥 ∈ 𝑆 ) → ( 𝑥 𝑅 𝐵 ) = 𝑥 ) | |
| 5 | 2 | ffnd | ⊢ ( 𝜑 → 𝐹 Fn 𝐴 ) |
| 6 | fnconstg | ⊢ ( 𝐵 ∈ 𝑊 → ( 𝐴 × { 𝐵 } ) Fn 𝐴 ) | |
| 7 | 3 6 | syl | ⊢ ( 𝜑 → ( 𝐴 × { 𝐵 } ) Fn 𝐴 ) |
| 8 | eqidd | ⊢ ( ( 𝜑 ∧ 𝑤 ∈ 𝐴 ) → ( 𝐹 ‘ 𝑤 ) = ( 𝐹 ‘ 𝑤 ) ) | |
| 9 | fvconst2g | ⊢ ( ( 𝐵 ∈ 𝑊 ∧ 𝑤 ∈ 𝐴 ) → ( ( 𝐴 × { 𝐵 } ) ‘ 𝑤 ) = 𝐵 ) | |
| 10 | 3 9 | sylan | ⊢ ( ( 𝜑 ∧ 𝑤 ∈ 𝐴 ) → ( ( 𝐴 × { 𝐵 } ) ‘ 𝑤 ) = 𝐵 ) |
| 11 | 4 | ralrimiva | ⊢ ( 𝜑 → ∀ 𝑥 ∈ 𝑆 ( 𝑥 𝑅 𝐵 ) = 𝑥 ) |
| 12 | 2 | ffvelcdmda | ⊢ ( ( 𝜑 ∧ 𝑤 ∈ 𝐴 ) → ( 𝐹 ‘ 𝑤 ) ∈ 𝑆 ) |
| 13 | oveq1 | ⊢ ( 𝑥 = ( 𝐹 ‘ 𝑤 ) → ( 𝑥 𝑅 𝐵 ) = ( ( 𝐹 ‘ 𝑤 ) 𝑅 𝐵 ) ) | |
| 14 | id | ⊢ ( 𝑥 = ( 𝐹 ‘ 𝑤 ) → 𝑥 = ( 𝐹 ‘ 𝑤 ) ) | |
| 15 | 13 14 | eqeq12d | ⊢ ( 𝑥 = ( 𝐹 ‘ 𝑤 ) → ( ( 𝑥 𝑅 𝐵 ) = 𝑥 ↔ ( ( 𝐹 ‘ 𝑤 ) 𝑅 𝐵 ) = ( 𝐹 ‘ 𝑤 ) ) ) |
| 16 | 15 | rspccva | ⊢ ( ( ∀ 𝑥 ∈ 𝑆 ( 𝑥 𝑅 𝐵 ) = 𝑥 ∧ ( 𝐹 ‘ 𝑤 ) ∈ 𝑆 ) → ( ( 𝐹 ‘ 𝑤 ) 𝑅 𝐵 ) = ( 𝐹 ‘ 𝑤 ) ) |
| 17 | 11 12 16 | syl2an2r | ⊢ ( ( 𝜑 ∧ 𝑤 ∈ 𝐴 ) → ( ( 𝐹 ‘ 𝑤 ) 𝑅 𝐵 ) = ( 𝐹 ‘ 𝑤 ) ) |
| 18 | 1 5 7 5 8 10 17 | offveq | ⊢ ( 𝜑 → ( 𝐹 ∘f 𝑅 ( 𝐴 × { 𝐵 } ) ) = 𝐹 ) |