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| Mirrors > Home > MPE Home > Th. List > ssun | Structured version Visualization version GIF version | ||
| Description: A condition that implies inclusion in the union of two classes. (Contributed by NM, 23-Nov-2003.) |
| Ref | Expression |
|---|---|
| ssun | ⊢ ((𝐴 ⊆ 𝐵 ∨ 𝐴 ⊆ 𝐶) → 𝐴 ⊆ (𝐵 ∪ 𝐶)) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ssun3 4180 | . 2 ⊢ (𝐴 ⊆ 𝐵 → 𝐴 ⊆ (𝐵 ∪ 𝐶)) | |
| 2 | ssun4 4181 | . 2 ⊢ (𝐴 ⊆ 𝐶 → 𝐴 ⊆ (𝐵 ∪ 𝐶)) | |
| 3 | 1, 2 | jaoi 858 | 1 ⊢ ((𝐴 ⊆ 𝐵 ∨ 𝐴 ⊆ 𝐶) → 𝐴 ⊆ (𝐵 ∪ 𝐶)) |
| Colors of variables: wff setvar class |
| Syntax hints: → wi 4 ∨ wo 848 ∪ cun 3949 ⊆ wss 3951 |
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1795 ax-4 1809 ax-5 1910 ax-6 1967 ax-7 2007 ax-8 2110 ax-9 2118 ax-ext 2708 |
| This theorem depends on definitions: df-bi 207 df-an 396 df-or 849 df-tru 1543 df-ex 1780 df-sb 2065 df-clab 2715 df-cleq 2729 df-clel 2816 df-v 3482 df-un 3956 df-ss 3968 |
| This theorem is referenced by: pwssun 5575 ordssun 6486 padct 32731 |
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