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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 3955 | . 2 ⊢ ((𝐴 ∪ 𝐵) ⊆ 𝐶 ↔ ∀𝑥(𝑥 ∈ (𝐴 ∪ 𝐵) → 𝑥 ∈ 𝐶)) | |
2 | 19.26 1871 | . . 3 ⊢ (∀𝑥((𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶) ∧ (𝑥 ∈ 𝐵 → 𝑥 ∈ 𝐶)) ↔ (∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶) ∧ ∀𝑥(𝑥 ∈ 𝐵 → 𝑥 ∈ 𝐶))) | |
3 | elunant 4154 | . . . 4 ⊢ ((𝑥 ∈ (𝐴 ∪ 𝐵) → 𝑥 ∈ 𝐶) ↔ ((𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶) ∧ (𝑥 ∈ 𝐵 → 𝑥 ∈ 𝐶))) | |
4 | 3 | albii 1820 | . . 3 ⊢ (∀𝑥(𝑥 ∈ (𝐴 ∪ 𝐵) → 𝑥 ∈ 𝐶) ↔ ∀𝑥((𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶) ∧ (𝑥 ∈ 𝐵 → 𝑥 ∈ 𝐶))) |
5 | dfss2 3955 | . . . 4 ⊢ (𝐴 ⊆ 𝐶 ↔ ∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶)) | |
6 | dfss2 3955 | . . . 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 1535 ∈ wcel 2114 ∪ cun 3934 ⊆ wss 3936 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1796 ax-4 1810 ax-5 1911 ax-6 1970 ax-7 2015 ax-8 2116 ax-9 2124 ax-10 2145 ax-11 2161 ax-12 2177 ax-ext 2793 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-tru 1540 df-ex 1781 df-nf 1785 df-sb 2070 df-clab 2800 df-cleq 2814 df-clel 2893 df-nfc 2963 df-v 3496 df-un 3941 df-in 3943 df-ss 3952 |
This theorem is referenced by: unssi 4161 unssd 4162 unssad 4163 unssbd 4164 nsspssun 4234 uneqin 4255 prssg 4752 ssunsn2 4760 tpss 4768 iunopeqop 5411 pwundifOLD 5457 eqrelrel 5670 xpsspw 5682 relun 5684 relcoi2 6128 pwuncl 7492 fnsuppres 7857 wfrlem15 7969 dfer2 8290 isinf 8731 trcl 9170 supxrun 12710 trclun 14374 isumltss 15203 rpnnen2lem12 15578 lcmfunsnlem 15985 lcmfun 15989 coprmprod 16005 coprmproddvdslem 16006 lubun 17733 isipodrs 17771 ipodrsima 17775 aspval2 20127 unocv 20824 uncld 21649 restntr 21790 cmpcld 22010 uncmp 22011 ufprim 22517 tsmsfbas 22736 ovolctb2 24093 ovolun 24100 unmbl 24138 plyun0 24787 sshjcl 29132 sshjval2 29188 shlub 29191 ssjo 29224 spanuni 29321 cntzun 30695 dfon2lem3 33030 dfon2lem7 33034 noextendseq 33174 noresle 33200 clsun 33676 lindsadd 34900 lindsenlbs 34902 mblfinlem3 34946 ismblfin 34948 paddssat 36965 pclunN 37049 paddunN 37078 poldmj1N 37079 pclfinclN 37101 lsmfgcl 39694 ssuncl 39949 sssymdifcl 39951 undmrnresiss 39984 mptrcllem 39993 cnvrcl0 40005 dfrtrcl5 40009 brtrclfv2 40092 unhe1 40151 dffrege76 40305 uneqsn 40393 mnurndlem1 40637 setrec1lem4 44813 elpglem2 44834 |
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