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| Mirrors > Home > MPE Home > Th. List > coeq2 | Structured version Visualization version GIF version | ||
| Description: Equality theorem for composition of two classes. (Contributed by NM, 3-Jan-1997.) |
| Ref | Expression |
|---|---|
| coeq2 | ⊢ (𝐴 = 𝐵 → (𝐶 ∘ 𝐴) = (𝐶 ∘ 𝐵)) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | coss2 5799 | . . 3 ⊢ (𝐴 ⊆ 𝐵 → (𝐶 ∘ 𝐴) ⊆ (𝐶 ∘ 𝐵)) | |
| 2 | coss2 5799 | . . 3 ⊢ (𝐵 ⊆ 𝐴 → (𝐶 ∘ 𝐵) ⊆ (𝐶 ∘ 𝐴)) | |
| 3 | 1, 2 | anim12i 613 | . 2 ⊢ ((𝐴 ⊆ 𝐵 ∧ 𝐵 ⊆ 𝐴) → ((𝐶 ∘ 𝐴) ⊆ (𝐶 ∘ 𝐵) ∧ (𝐶 ∘ 𝐵) ⊆ (𝐶 ∘ 𝐴))) |
| 4 | eqss 3951 | . 2 ⊢ (𝐴 = 𝐵 ↔ (𝐴 ⊆ 𝐵 ∧ 𝐵 ⊆ 𝐴)) | |
| 5 | eqss 3951 | . 2 ⊢ ((𝐶 ∘ 𝐴) = (𝐶 ∘ 𝐵) ↔ ((𝐶 ∘ 𝐴) ⊆ (𝐶 ∘ 𝐵) ∧ (𝐶 ∘ 𝐵) ⊆ (𝐶 ∘ 𝐴))) | |
| 6 | 3, 4, 5 | 3imtr4i 292 | 1 ⊢ (𝐴 = 𝐵 → (𝐶 ∘ 𝐴) = (𝐶 ∘ 𝐵)) |
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