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Mirrors > Home > ILE Home > Th. List > ssini | GIF version |
Description: An inference showing that a subclass of two classes is a subclass of their intersection. (Contributed by NM, 24-Nov-2003.) |
Ref | Expression |
---|---|
ssini.1 | ⊢ 𝐴 ⊆ 𝐵 |
ssini.2 | ⊢ 𝐴 ⊆ 𝐶 |
Ref | Expression |
---|---|
ssini | ⊢ 𝐴 ⊆ (𝐵 ∩ 𝐶) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ssini.1 | . . 3 ⊢ 𝐴 ⊆ 𝐵 | |
2 | ssini.2 | . . 3 ⊢ 𝐴 ⊆ 𝐶 | |
3 | 1, 2 | pm3.2i 272 | . 2 ⊢ (𝐴 ⊆ 𝐵 ∧ 𝐴 ⊆ 𝐶) |
4 | ssin 3369 | . 2 ⊢ ((𝐴 ⊆ 𝐵 ∧ 𝐴 ⊆ 𝐶) ↔ 𝐴 ⊆ (𝐵 ∩ 𝐶)) | |
5 | 3, 4 | mpbi 145 | 1 ⊢ 𝐴 ⊆ (𝐵 ∩ 𝐶) |
Colors of variables: wff set class |
Syntax hints: ∧ wa 104 ∩ cin 3140 ⊆ wss 3141 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-io 710 ax-5 1457 ax-7 1458 ax-gen 1459 ax-ie1 1503 ax-ie2 1504 ax-8 1514 ax-10 1515 ax-11 1516 ax-i12 1517 ax-bndl 1519 ax-4 1520 ax-17 1536 ax-i9 1540 ax-ial 1544 ax-i5r 1545 ax-ext 2169 |
This theorem depends on definitions: df-bi 117 df-tru 1366 df-nf 1471 df-sb 1773 df-clab 2174 df-cleq 2180 df-clel 2183 df-nfc 2318 df-v 2751 df-in 3147 df-ss 3154 |
This theorem is referenced by: inv1 3471 |
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