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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 3968 | . 2 ⊢ ((𝐴 ∪ 𝐵) ⊆ 𝐶 ↔ ∀𝑥(𝑥 ∈ (𝐴 ∪ 𝐵) → 𝑥 ∈ 𝐶)) | |
2 | 19.26 1874 | . . 3 ⊢ (∀𝑥((𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶) ∧ (𝑥 ∈ 𝐵 → 𝑥 ∈ 𝐶)) ↔ (∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶) ∧ ∀𝑥(𝑥 ∈ 𝐵 → 𝑥 ∈ 𝐶))) | |
3 | elunant 4178 | . . . 4 ⊢ ((𝑥 ∈ (𝐴 ∪ 𝐵) → 𝑥 ∈ 𝐶) ↔ ((𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶) ∧ (𝑥 ∈ 𝐵 → 𝑥 ∈ 𝐶))) | |
4 | 3 | albii 1822 | . . 3 ⊢ (∀𝑥(𝑥 ∈ (𝐴 ∪ 𝐵) → 𝑥 ∈ 𝐶) ↔ ∀𝑥((𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶) ∧ (𝑥 ∈ 𝐵 → 𝑥 ∈ 𝐶))) |
5 | dfss2 3968 | . . . 4 ⊢ (𝐴 ⊆ 𝐶 ↔ ∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶)) | |
6 | dfss2 3968 | . . . 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 303 | . 2 ⊢ (∀𝑥(𝑥 ∈ (𝐴 ∪ 𝐵) → 𝑥 ∈ 𝐶) ↔ (𝐴 ⊆ 𝐶 ∧ 𝐵 ⊆ 𝐶)) |
9 | 1, 8 | bitr2i 276 | 1 ⊢ ((𝐴 ⊆ 𝐶 ∧ 𝐵 ⊆ 𝐶) ↔ (𝐴 ∪ 𝐵) ⊆ 𝐶) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 205 ∧ wa 397 ∀wal 1540 ∈ wcel 2107 ∪ cun 3946 ⊆ wss 3948 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1798 ax-4 1812 ax-5 1914 ax-6 1972 ax-7 2012 ax-8 2109 ax-9 2117 ax-ext 2704 |
This theorem depends on definitions: df-bi 206 df-an 398 df-or 847 df-tru 1545 df-ex 1783 df-sb 2069 df-clab 2711 df-cleq 2725 df-clel 2811 df-v 3477 df-un 3953 df-in 3955 df-ss 3965 |
This theorem is referenced by: unssi 4185 unssd 4186 unssad 4187 unssbd 4188 nsspssun 4257 uneqin 4278 prssg 4822 ssunsn2 4830 tpss 4838 iunopeqop 5521 eqrelrel 5796 xpsspw 5808 relun 5810 relcoi2 6274 pwuncl 7754 fnsuppres 8173 wfrlem15OLD 8320 naddov3 8676 naddasslem1 8690 naddasslem2 8691 dfer2 8701 isinf 9257 isinfOLD 9258 trcl 9720 supxrun 13292 trclun 14958 isumltss 15791 rpnnen2lem12 16165 lcmfunsnlem 16575 lcmfun 16579 coprmprod 16595 coprmproddvdslem 16596 lubun 18465 isipodrs 18487 ipodrsima 18491 unocv 21225 aspval2 21444 uncld 22537 restntr 22678 cmpcld 22898 uncmp 22899 ufprim 23405 tsmsfbas 23624 ovolctb2 25001 ovolun 25008 unmbl 25046 plyun0 25703 noextendseq 27160 noresle 27190 madebdayim 27372 sshjcl 30596 sshjval2 30652 shlub 30655 ssjo 30688 spanuni 30785 cntzun 32200 dfon2lem3 34746 dfon2lem7 34750 clsun 35202 lindsadd 36470 lindsenlbs 36472 mblfinlem3 36516 ismblfin 36518 paddssat 38674 pclunN 38758 paddunN 38787 poldmj1N 38788 pclfinclN 38810 lsmfgcl 41802 tfsconcatrnss 42086 ssuncl 42307 sssymdifcl 42309 undmrnresiss 42341 mptrcllem 42350 cnvrcl0 42362 dfrtrcl5 42366 brtrclfv2 42464 unhe1 42522 dffrege76 42676 uneqsn 42762 mnurndlem1 43026 setrec1lem4 47689 elpglem2 47711 |
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