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Mirrors > Home > ILE Home > Th. List > unssad | GIF version |
Description: If (𝐴 ∪ 𝐵) is contained in 𝐶, so is 𝐴. One-way deduction form of unss 3160. Partial converse of unssd 3162. (Contributed by David Moews, 1-May-2017.) |
Ref | Expression |
---|---|
unssad.1 | ⊢ (𝜑 → (𝐴 ∪ 𝐵) ⊆ 𝐶) |
Ref | Expression |
---|---|
unssad | ⊢ (𝜑 → 𝐴 ⊆ 𝐶) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | unssad.1 | . . 3 ⊢ (𝜑 → (𝐴 ∪ 𝐵) ⊆ 𝐶) | |
2 | unss 3160 | . . 3 ⊢ ((𝐴 ⊆ 𝐶 ∧ 𝐵 ⊆ 𝐶) ↔ (𝐴 ∪ 𝐵) ⊆ 𝐶) | |
3 | 1, 2 | sylibr 132 | . 2 ⊢ (𝜑 → (𝐴 ⊆ 𝐶 ∧ 𝐵 ⊆ 𝐶)) |
4 | 3 | simpld 110 | 1 ⊢ (𝜑 → 𝐴 ⊆ 𝐶) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 102 ∪ cun 2984 ⊆ wss 2986 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 104 ax-ia2 105 ax-ia3 106 ax-io 663 ax-5 1379 ax-7 1380 ax-gen 1381 ax-ie1 1425 ax-ie2 1426 ax-8 1438 ax-10 1439 ax-11 1440 ax-i12 1441 ax-bndl 1442 ax-4 1443 ax-17 1462 ax-i9 1466 ax-ial 1470 ax-i5r 1471 ax-ext 2067 |
This theorem depends on definitions: df-bi 115 df-tru 1290 df-nf 1393 df-sb 1690 df-clab 2072 df-cleq 2078 df-clel 2081 df-nfc 2214 df-v 2616 df-un 2990 df-in 2992 df-ss 2999 |
This theorem is referenced by: ersym 6237 findcard2d 6540 findcard2sd 6541 diffifi 6543 |
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