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| Mirrors > Home > MPE Home > Th. List > syl5sseq | Structured version Visualization version GIF version | ||
| Description: Subclass transitivity deduction. (Contributed by Jonathan Ben-Naim, 3-Jun-2011.) |
| Ref | Expression |
|---|---|
| syl5sseq.1 | ⊢ 𝐵 ⊆ 𝐴 |
| syl5sseq.2 | ⊢ (𝜑 → 𝐴 = 𝐶) |
| Ref | Expression |
|---|---|
| syl5sseq | ⊢ (𝜑 → 𝐵 ⊆ 𝐶) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | syl5sseq.2 | . 2 ⊢ (𝜑 → 𝐴 = 𝐶) | |
| 2 | syl5sseq.1 | . 2 ⊢ 𝐵 ⊆ 𝐴 | |
| 3 | sseq2 3627 | . . 3 ⊢ (𝐴 = 𝐶 → (𝐵 ⊆ 𝐴 ↔ 𝐵 ⊆ 𝐶)) | |
| 4 | 3 | biimpa 501 | . 2 ⊢ ((𝐴 = 𝐶 ∧ 𝐵 ⊆ 𝐴) → 𝐵 ⊆ 𝐶) |
| 5 | 1, 2, 4 | sylancl 694 | 1 ⊢ (𝜑 → 𝐵 ⊆ 𝐶) |
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