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Description: Lemma for fcoresf1 . (Contributed by AV, 18-Sep-2024)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | fcores.f | ⊢ ( 𝜑 → 𝐹 : 𝐴 ⟶ 𝐵 ) | |
| fcores.e | ⊢ 𝐸 = ( ran 𝐹 ∩ 𝐶 ) | ||
| fcores.p | ⊢ 𝑃 = ( ◡ 𝐹 “ 𝐶 ) | ||
| fcores.x | ⊢ 𝑋 = ( 𝐹 ↾ 𝑃 ) | ||
| fcores.g | ⊢ ( 𝜑 → 𝐺 : 𝐶 ⟶ 𝐷 ) | ||
| fcores.y | ⊢ 𝑌 = ( 𝐺 ↾ 𝐸 ) | ||
| Assertion | fcoresf1lem | ⊢ ( ( 𝜑 ∧ 𝑍 ∈ 𝑃 ) → ( ( 𝐺 ∘ 𝐹 ) ‘ 𝑍 ) = ( 𝑌 ‘ ( 𝑋 ‘ 𝑍 ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | fcores.f | ⊢ ( 𝜑 → 𝐹 : 𝐴 ⟶ 𝐵 ) | |
| 2 | fcores.e | ⊢ 𝐸 = ( ran 𝐹 ∩ 𝐶 ) | |
| 3 | fcores.p | ⊢ 𝑃 = ( ◡ 𝐹 “ 𝐶 ) | |
| 4 | fcores.x | ⊢ 𝑋 = ( 𝐹 ↾ 𝑃 ) | |
| 5 | fcores.g | ⊢ ( 𝜑 → 𝐺 : 𝐶 ⟶ 𝐷 ) | |
| 6 | fcores.y | ⊢ 𝑌 = ( 𝐺 ↾ 𝐸 ) | |
| 7 | 1 2 3 4 5 6 | fcores | ⊢ ( 𝜑 → ( 𝐺 ∘ 𝐹 ) = ( 𝑌 ∘ 𝑋 ) ) |
| 8 | 7 | fveq1d | ⊢ ( 𝜑 → ( ( 𝐺 ∘ 𝐹 ) ‘ 𝑍 ) = ( ( 𝑌 ∘ 𝑋 ) ‘ 𝑍 ) ) |
| 9 | 8 | adantr | ⊢ ( ( 𝜑 ∧ 𝑍 ∈ 𝑃 ) → ( ( 𝐺 ∘ 𝐹 ) ‘ 𝑍 ) = ( ( 𝑌 ∘ 𝑋 ) ‘ 𝑍 ) ) |
| 10 | 1 2 3 4 | fcoreslem3 | ⊢ ( 𝜑 → 𝑋 : 𝑃 –onto→ 𝐸 ) |
| 11 | fof | ⊢ ( 𝑋 : 𝑃 –onto→ 𝐸 → 𝑋 : 𝑃 ⟶ 𝐸 ) | |
| 12 | 10 11 | syl | ⊢ ( 𝜑 → 𝑋 : 𝑃 ⟶ 𝐸 ) |
| 13 | 12 | adantr | ⊢ ( ( 𝜑 ∧ 𝑍 ∈ 𝑃 ) → 𝑋 : 𝑃 ⟶ 𝐸 ) |
| 14 | simpr | ⊢ ( ( 𝜑 ∧ 𝑍 ∈ 𝑃 ) → 𝑍 ∈ 𝑃 ) | |
| 15 | 13 14 | fvco3d | ⊢ ( ( 𝜑 ∧ 𝑍 ∈ 𝑃 ) → ( ( 𝑌 ∘ 𝑋 ) ‘ 𝑍 ) = ( 𝑌 ‘ ( 𝑋 ‘ 𝑍 ) ) ) |
| 16 | 9 15 | eqtrd | ⊢ ( ( 𝜑 ∧ 𝑍 ∈ 𝑃 ) → ( ( 𝐺 ∘ 𝐹 ) ‘ 𝑍 ) = ( 𝑌 ‘ ( 𝑋 ‘ 𝑍 ) ) ) |