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Mirrors > Home > MPE Home > Th. List > sstri | Structured version Visualization version GIF version |
Description: Subclass transitivity inference. (Contributed by NM, 5-May-2000.) |
Ref | Expression |
---|---|
sstri.1 | ⊢ 𝐴 ⊆ 𝐵 |
sstri.2 | ⊢ 𝐵 ⊆ 𝐶 |
Ref | Expression |
---|---|
sstri | ⊢ 𝐴 ⊆ 𝐶 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | sstri.1 | . 2 ⊢ 𝐴 ⊆ 𝐵 | |
2 | sstri.2 | . 2 ⊢ 𝐵 ⊆ 𝐶 | |
3 | sstr2 3929 | . 2 ⊢ (𝐴 ⊆ 𝐵 → (𝐵 ⊆ 𝐶 → 𝐴 ⊆ 𝐶)) | |
4 | 1, 2, 3 | mp2 9 | 1 ⊢ 𝐴 ⊆ 𝐶 |
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