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Description: Closure law for an operation. (Contributed by NM, 19-Apr-2007) (Proof shortened by AV, 9-Mar-2025)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | fovcl.1 | ⊢ 𝐹 : ( 𝑅 × 𝑆 ) ⟶ 𝐶 | |
| Assertion | fovcl | ⊢ ( ( 𝐴 ∈ 𝑅 ∧ 𝐵 ∈ 𝑆 ) → ( 𝐴 𝐹 𝐵 ) ∈ 𝐶 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | fovcl.1 | ⊢ 𝐹 : ( 𝑅 × 𝑆 ) ⟶ 𝐶 | |
| 2 | 1 | a1i | ⊢ ( 𝐴 ∈ 𝑅 → 𝐹 : ( 𝑅 × 𝑆 ) ⟶ 𝐶 ) |
| 3 | 2 | fovcld | ⊢ ( ( 𝐴 ∈ 𝑅 ∧ 𝐴 ∈ 𝑅 ∧ 𝐵 ∈ 𝑆 ) → ( 𝐴 𝐹 𝐵 ) ∈ 𝐶 ) |
| 4 | 3 | 3anidm12 | ⊢ ( ( 𝐴 ∈ 𝑅 ∧ 𝐵 ∈ 𝑆 ) → ( 𝐴 𝐹 𝐵 ) ∈ 𝐶 ) |