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Mirrors > Home > MPE Home > Th. List > unss | Structured version Visualization version GIF version |
Description: The union of two subclasses is a subclass. Theorem 27 of [Suppes] p. 27 and its converse. (Contributed by NM, 11-Jun-2004.) |
Ref | Expression |
---|---|
unss | ⊢ ((𝐴 ⊆ 𝐶 ∧ 𝐵 ⊆ 𝐶) ↔ (𝐴 ∪ 𝐵) ⊆ 𝐶) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | dfss2 3954 | . 2 ⊢ ((𝐴 ∪ 𝐵) ⊆ 𝐶 ↔ ∀𝑥(𝑥 ∈ (𝐴 ∪ 𝐵) → 𝑥 ∈ 𝐶)) | |
2 | 19.26 1867 | . . 3 ⊢ (∀𝑥((𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶) ∧ (𝑥 ∈ 𝐵 → 𝑥 ∈ 𝐶)) ↔ (∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶) ∧ ∀𝑥(𝑥 ∈ 𝐵 → 𝑥 ∈ 𝐶))) | |
3 | elunant 4153 | . . . 4 ⊢ ((𝑥 ∈ (𝐴 ∪ 𝐵) → 𝑥 ∈ 𝐶) ↔ ((𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶) ∧ (𝑥 ∈ 𝐵 → 𝑥 ∈ 𝐶))) | |
4 | 3 | albii 1816 | . . 3 ⊢ (∀𝑥(𝑥 ∈ (𝐴 ∪ 𝐵) → 𝑥 ∈ 𝐶) ↔ ∀𝑥((𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶) ∧ (𝑥 ∈ 𝐵 → 𝑥 ∈ 𝐶))) |
5 | dfss2 3954 | . . . 4 ⊢ (𝐴 ⊆ 𝐶 ↔ ∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶)) | |
6 | dfss2 3954 | . . . 4 ⊢ (𝐵 ⊆ 𝐶 ↔ ∀𝑥(𝑥 ∈ 𝐵 → 𝑥 ∈ 𝐶)) | |
7 | 5, 6 | anbi12i 628 | . . 3 ⊢ ((𝐴 ⊆ 𝐶 ∧ 𝐵 ⊆ 𝐶) ↔ (∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶) ∧ ∀𝑥(𝑥 ∈ 𝐵 → 𝑥 ∈ 𝐶))) |
8 | 2, 4, 7 | 3bitr4i 305 | . 2 ⊢ (∀𝑥(𝑥 ∈ (𝐴 ∪ 𝐵) → 𝑥 ∈ 𝐶) ↔ (𝐴 ⊆ 𝐶 ∧ 𝐵 ⊆ 𝐶)) |
9 | 1, 8 | bitr2i 278 | 1 ⊢ ((𝐴 ⊆ 𝐶 ∧ 𝐵 ⊆ 𝐶) ↔ (𝐴 ∪ 𝐵) ⊆ 𝐶) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 208 ∧ wa 398 ∀wal 1531 ∈ wcel 2110 ∪ cun 3933 ⊆ wss 3935 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1792 ax-4 1806 ax-5 1907 ax-6 1966 ax-7 2011 ax-8 2112 ax-9 2120 ax-10 2141 ax-11 2157 ax-12 2173 ax-ext 2793 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-tru 1536 df-ex 1777 df-nf 1781 df-sb 2066 df-clab 2800 df-cleq 2814 df-clel 2893 df-nfc 2963 df-v 3496 df-un 3940 df-in 3942 df-ss 3951 |
This theorem is referenced by: unssi 4160 unssd 4161 unssad 4162 unssbd 4163 nsspssun 4233 uneqin 4254 prssg 4745 ssunsn2 4753 tpss 4761 iunopeqop 5403 pwundifOLD 5451 eqrelrel 5664 xpsspw 5676 relun 5678 relcoi2 6122 pwuncl 7486 fnsuppres 7851 wfrlem15 7963 dfer2 8284 isinf 8725 trcl 9164 supxrun 12703 trclun 14368 isumltss 15197 rpnnen2lem12 15572 lcmfunsnlem 15979 lcmfun 15983 coprmprod 15999 coprmproddvdslem 16000 lubun 17727 isipodrs 17765 ipodrsima 17769 aspval2 20121 unocv 20818 uncld 21643 restntr 21784 cmpcld 22004 uncmp 22005 ufprim 22511 tsmsfbas 22730 ovolctb2 24087 ovolun 24094 unmbl 24132 plyun0 24781 sshjcl 29126 sshjval2 29182 shlub 29185 ssjo 29218 spanuni 29315 cntzun 30690 dfon2lem3 33025 dfon2lem7 33029 noextendseq 33169 noresle 33195 clsun 33671 lindsadd 34879 lindsenlbs 34881 mblfinlem3 34925 ismblfin 34927 paddssat 36944 pclunN 37028 paddunN 37057 poldmj1N 37058 pclfinclN 37080 lsmfgcl 39667 ssuncl 39922 sssymdifcl 39924 undmrnresiss 39957 mptrcllem 39966 cnvrcl0 39978 dfrtrcl5 39982 brtrclfv2 40065 unhe1 40124 dffrege76 40278 uneqsn 40366 mnurndlem1 40610 setrec1lem4 44787 elpglem2 44808 |
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