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Description: The restriction of an operation is an operation. (Contributed by NM, 1-Feb-2008) (Revised by AV, 19-Oct-2021)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | oprres.v | ⊢ ( ( 𝜑 ∧ 𝑥 ∈ 𝑌 ∧ 𝑦 ∈ 𝑌 ) → ( 𝑥 𝐹 𝑦 ) = ( 𝑥 𝐺 𝑦 ) ) | |
| oprres.s | ⊢ ( 𝜑 → 𝑌 ⊆ 𝑋 ) | ||
| oprres.f | ⊢ ( 𝜑 → 𝐹 : ( 𝑌 × 𝑌 ) ⟶ 𝑅 ) | ||
| oprres.g | ⊢ ( 𝜑 → 𝐺 : ( 𝑋 × 𝑋 ) ⟶ 𝑆 ) | ||
| Assertion | oprres | ⊢ ( 𝜑 → 𝐹 = ( 𝐺 ↾ ( 𝑌 × 𝑌 ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | oprres.v | ⊢ ( ( 𝜑 ∧ 𝑥 ∈ 𝑌 ∧ 𝑦 ∈ 𝑌 ) → ( 𝑥 𝐹 𝑦 ) = ( 𝑥 𝐺 𝑦 ) ) | |
| 2 | oprres.s | ⊢ ( 𝜑 → 𝑌 ⊆ 𝑋 ) | |
| 3 | oprres.f | ⊢ ( 𝜑 → 𝐹 : ( 𝑌 × 𝑌 ) ⟶ 𝑅 ) | |
| 4 | oprres.g | ⊢ ( 𝜑 → 𝐺 : ( 𝑋 × 𝑋 ) ⟶ 𝑆 ) | |
| 5 | 1 | 3expb | ⊢ ( ( 𝜑 ∧ ( 𝑥 ∈ 𝑌 ∧ 𝑦 ∈ 𝑌 ) ) → ( 𝑥 𝐹 𝑦 ) = ( 𝑥 𝐺 𝑦 ) ) |
| 6 | ovres | ⊢ ( ( 𝑥 ∈ 𝑌 ∧ 𝑦 ∈ 𝑌 ) → ( 𝑥 ( 𝐺 ↾ ( 𝑌 × 𝑌 ) ) 𝑦 ) = ( 𝑥 𝐺 𝑦 ) ) | |
| 7 | 6 | adantl | ⊢ ( ( 𝜑 ∧ ( 𝑥 ∈ 𝑌 ∧ 𝑦 ∈ 𝑌 ) ) → ( 𝑥 ( 𝐺 ↾ ( 𝑌 × 𝑌 ) ) 𝑦 ) = ( 𝑥 𝐺 𝑦 ) ) |
| 8 | 5 7 | eqtr4d | ⊢ ( ( 𝜑 ∧ ( 𝑥 ∈ 𝑌 ∧ 𝑦 ∈ 𝑌 ) ) → ( 𝑥 𝐹 𝑦 ) = ( 𝑥 ( 𝐺 ↾ ( 𝑌 × 𝑌 ) ) 𝑦 ) ) |
| 9 | 8 | ralrimivva | ⊢ ( 𝜑 → ∀ 𝑥 ∈ 𝑌 ∀ 𝑦 ∈ 𝑌 ( 𝑥 𝐹 𝑦 ) = ( 𝑥 ( 𝐺 ↾ ( 𝑌 × 𝑌 ) ) 𝑦 ) ) |
| 10 | eqid | ⊢ ( 𝑌 × 𝑌 ) = ( 𝑌 × 𝑌 ) | |
| 11 | 9 10 | jctil | ⊢ ( 𝜑 → ( ( 𝑌 × 𝑌 ) = ( 𝑌 × 𝑌 ) ∧ ∀ 𝑥 ∈ 𝑌 ∀ 𝑦 ∈ 𝑌 ( 𝑥 𝐹 𝑦 ) = ( 𝑥 ( 𝐺 ↾ ( 𝑌 × 𝑌 ) ) 𝑦 ) ) ) |
| 12 | 3 | ffnd | ⊢ ( 𝜑 → 𝐹 Fn ( 𝑌 × 𝑌 ) ) |
| 13 | 4 | ffnd | ⊢ ( 𝜑 → 𝐺 Fn ( 𝑋 × 𝑋 ) ) |
| 14 | xpss12 | ⊢ ( ( 𝑌 ⊆ 𝑋 ∧ 𝑌 ⊆ 𝑋 ) → ( 𝑌 × 𝑌 ) ⊆ ( 𝑋 × 𝑋 ) ) | |
| 15 | 2 2 14 | syl2anc | ⊢ ( 𝜑 → ( 𝑌 × 𝑌 ) ⊆ ( 𝑋 × 𝑋 ) ) |
| 16 | fnssres | ⊢ ( ( 𝐺 Fn ( 𝑋 × 𝑋 ) ∧ ( 𝑌 × 𝑌 ) ⊆ ( 𝑋 × 𝑋 ) ) → ( 𝐺 ↾ ( 𝑌 × 𝑌 ) ) Fn ( 𝑌 × 𝑌 ) ) | |
| 17 | 13 15 16 | syl2anc | ⊢ ( 𝜑 → ( 𝐺 ↾ ( 𝑌 × 𝑌 ) ) Fn ( 𝑌 × 𝑌 ) ) |
| 18 | eqfnov | ⊢ ( ( 𝐹 Fn ( 𝑌 × 𝑌 ) ∧ ( 𝐺 ↾ ( 𝑌 × 𝑌 ) ) Fn ( 𝑌 × 𝑌 ) ) → ( 𝐹 = ( 𝐺 ↾ ( 𝑌 × 𝑌 ) ) ↔ ( ( 𝑌 × 𝑌 ) = ( 𝑌 × 𝑌 ) ∧ ∀ 𝑥 ∈ 𝑌 ∀ 𝑦 ∈ 𝑌 ( 𝑥 𝐹 𝑦 ) = ( 𝑥 ( 𝐺 ↾ ( 𝑌 × 𝑌 ) ) 𝑦 ) ) ) ) | |
| 19 | 12 17 18 | syl2anc | ⊢ ( 𝜑 → ( 𝐹 = ( 𝐺 ↾ ( 𝑌 × 𝑌 ) ) ↔ ( ( 𝑌 × 𝑌 ) = ( 𝑌 × 𝑌 ) ∧ ∀ 𝑥 ∈ 𝑌 ∀ 𝑦 ∈ 𝑌 ( 𝑥 𝐹 𝑦 ) = ( 𝑥 ( 𝐺 ↾ ( 𝑌 × 𝑌 ) ) 𝑦 ) ) ) ) |
| 20 | 11 19 | mpbird | ⊢ ( 𝜑 → 𝐹 = ( 𝐺 ↾ ( 𝑌 × 𝑌 ) ) ) |