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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 | df-ss 3979 | . 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 4193 | . . . 4 ⊢ ((𝑥 ∈ (𝐴 ∪ 𝐵) → 𝑥 ∈ 𝐶) ↔ ((𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶) ∧ (𝑥 ∈ 𝐵 → 𝑥 ∈ 𝐶))) | |
4 | 3 | albii 1815 | . . 3 ⊢ (∀𝑥(𝑥 ∈ (𝐴 ∪ 𝐵) → 𝑥 ∈ 𝐶) ↔ ∀𝑥((𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶) ∧ (𝑥 ∈ 𝐵 → 𝑥 ∈ 𝐶))) |
5 | df-ss 3979 | . . . 4 ⊢ (𝐴 ⊆ 𝐶 ↔ ∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶)) | |
6 | df-ss 3979 | . . . 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 206 ∧ wa 395 ∀wal 1534 ∈ wcel 2105 ∪ cun 3960 ⊆ wss 3962 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1791 ax-4 1805 ax-5 1907 ax-6 1964 ax-7 2004 ax-8 2107 ax-9 2115 ax-ext 2705 |
This theorem depends on definitions: df-bi 207 df-an 396 df-or 848 df-tru 1539 df-ex 1776 df-sb 2062 df-clab 2712 df-cleq 2726 df-clel 2813 df-v 3479 df-un 3967 df-ss 3979 |
This theorem is referenced by: unssi 4200 unssd 4201 unssad 4202 unssbd 4203 nsspssun 4273 uneqin 4294 prssg 4823 ssunsn2 4831 tpss 4841 iunopeqop 5530 eqrelrel 5809 xpsspw 5821 relun 5823 relcoi2 6298 pwuncl 7788 fnsuppres 8214 wfrlem15OLD 8361 naddov3 8716 naddasslem1 8730 naddasslem2 8731 dfer2 8744 isinf 9293 isinfOLD 9294 trcl 9765 supxrun 13354 trclun 15049 isumltss 15880 rpnnen2lem12 16257 lcmfunsnlem 16674 lcmfun 16678 coprmprod 16694 coprmproddvdslem 16695 lubun 18572 isipodrs 18594 ipodrsima 18598 unocv 21715 aspval2 21935 uncld 23064 restntr 23205 cmpcld 23425 uncmp 23426 ufprim 23932 tsmsfbas 24151 ovolctb2 25540 ovolun 25547 unmbl 25585 plyun0 26250 noextendseq 27726 noresle 27756 madebdayim 27940 sshjcl 31383 sshjval2 31439 shlub 31442 ssjo 31475 spanuni 31572 cntzun 33053 unitprodclb 33396 dfon2lem3 35766 dfon2lem7 35770 clsun 36310 lindsadd 37599 lindsenlbs 37601 mblfinlem3 37645 ismblfin 37647 paddssat 39796 pclunN 39880 paddunN 39909 poldmj1N 39910 pclfinclN 39932 lsmfgcl 43062 tfsconcatrnss 43339 ssuncl 43559 sssymdifcl 43561 undmrnresiss 43593 mptrcllem 43602 cnvrcl0 43614 dfrtrcl5 43618 brtrclfv2 43716 unhe1 43774 dffrege76 43928 uneqsn 44014 mnurndlem1 44276 setrec1lem4 48920 elpglem2 48942 |
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