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Mirrors > Home > MPE Home > Th. List > ssun3 | Structured version Visualization version GIF version |
Description: Subclass law for union of classes. (Contributed by NM, 5-Aug-1993.) |
Ref | Expression |
---|---|
ssun3 | ⊢ (𝐴 ⊆ 𝐵 → 𝐴 ⊆ (𝐵 ∪ 𝐶)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ssun1 4072 | . 2 ⊢ 𝐵 ⊆ (𝐵 ∪ 𝐶) | |
2 | sstr2 3894 | . 2 ⊢ (𝐴 ⊆ 𝐵 → (𝐵 ⊆ (𝐵 ∪ 𝐶) → 𝐴 ⊆ (𝐵 ∪ 𝐶))) | |
3 | 1, 2 | mpi 20 | 1 ⊢ (𝐴 ⊆ 𝐵 → 𝐴 ⊆ (𝐵 ∪ 𝐶)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∪ cun 3851 ⊆ wss 3853 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1803 ax-4 1817 ax-5 1918 ax-6 1976 ax-7 2018 ax-8 2114 ax-9 2122 ax-ext 2708 |
This theorem depends on definitions: df-bi 210 df-an 400 df-or 848 df-tru 1546 df-ex 1788 df-sb 2073 df-clab 2715 df-cleq 2728 df-clel 2809 df-v 3400 df-un 3858 df-in 3860 df-ss 3870 |
This theorem is referenced by: ssun 4089 ssunsn2 4726 xpsspw 5664 wfrlem15 8047 uncmp 22254 alexsubALTlem3 22900 sxbrsigalem0 31904 bnj1450 32697 fineqvac 32733 altxpsspw 33965 pibt2 35274 superuncl 40792 cnvtrcl0 40851 |
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