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Mirrors > Home > ILE Home > Th. List > unssbd | GIF version |
Description: If (𝐴 ∪ 𝐵) is contained in 𝐶, so is 𝐵. One-way deduction form of unss 3117. Partial converse of unssd 3119. (Contributed by David Moews, 1-May-2017.) |
Ref | Expression |
---|---|
unssad.1 | ⊢ (𝜑 → (𝐴 ∪ 𝐵) ⊆ 𝐶) |
Ref | Expression |
---|---|
unssbd | ⊢ (𝜑 → 𝐵 ⊆ 𝐶) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | unssad.1 | . . 3 ⊢ (𝜑 → (𝐴 ∪ 𝐵) ⊆ 𝐶) | |
2 | unss 3117 | . . 3 ⊢ ((𝐴 ⊆ 𝐶 ∧ 𝐵 ⊆ 𝐶) ↔ (𝐴 ∪ 𝐵) ⊆ 𝐶) | |
3 | 1, 2 | sylibr 137 | . 2 ⊢ (𝜑 → (𝐴 ⊆ 𝐶 ∧ 𝐵 ⊆ 𝐶)) |
4 | 3 | simprd 107 | 1 ⊢ (𝜑 → 𝐵 ⊆ 𝐶) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 97 ∪ cun 2915 ⊆ wss 2917 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 99 ax-ia2 100 ax-ia3 101 ax-io 630 ax-5 1336 ax-7 1337 ax-gen 1338 ax-ie1 1382 ax-ie2 1383 ax-8 1395 ax-10 1396 ax-11 1397 ax-i12 1398 ax-bndl 1399 ax-4 1400 ax-17 1419 ax-i9 1423 ax-ial 1427 ax-i5r 1428 ax-ext 2022 |
This theorem depends on definitions: df-bi 110 df-tru 1246 df-nf 1350 df-sb 1646 df-clab 2027 df-cleq 2033 df-clel 2036 df-nfc 2167 df-v 2559 df-un 2922 df-in 2924 df-ss 2931 |
This theorem is referenced by: eldifpw 4208 ertr 6121 diffifi 6351 |
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