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Mirrors > Home > MPE Home > Th. List > ssequn1 | Structured version Visualization version GIF version |
Description: A relationship between subclass and union. Theorem 26 of [Suppes] p. 27. (Contributed by NM, 30-Aug-1993.) (Proof shortened by Andrew Salmon, 26-Jun-2011.) |
Ref | Expression |
---|---|
ssequn1 | ⊢ (𝐴 ⊆ 𝐵 ↔ (𝐴 ∪ 𝐵) = 𝐵) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | bicom 212 | . . . 4 ⊢ ((𝑥 ∈ 𝐵 ↔ (𝑥 ∈ 𝐴 ∨ 𝑥 ∈ 𝐵)) ↔ ((𝑥 ∈ 𝐴 ∨ 𝑥 ∈ 𝐵) ↔ 𝑥 ∈ 𝐵)) | |
2 | pm4.72 920 | . . . 4 ⊢ ((𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐵) ↔ (𝑥 ∈ 𝐵 ↔ (𝑥 ∈ 𝐴 ∨ 𝑥 ∈ 𝐵))) | |
3 | elun 3753 | . . . . 5 ⊢ (𝑥 ∈ (𝐴 ∪ 𝐵) ↔ (𝑥 ∈ 𝐴 ∨ 𝑥 ∈ 𝐵)) | |
4 | 3 | bibi1i 328 | . . . 4 ⊢ ((𝑥 ∈ (𝐴 ∪ 𝐵) ↔ 𝑥 ∈ 𝐵) ↔ ((𝑥 ∈ 𝐴 ∨ 𝑥 ∈ 𝐵) ↔ 𝑥 ∈ 𝐵)) |
5 | 1, 2, 4 | 3bitr4i 292 | . . 3 ⊢ ((𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐵) ↔ (𝑥 ∈ (𝐴 ∪ 𝐵) ↔ 𝑥 ∈ 𝐵)) |
6 | 5 | albii 1747 | . 2 ⊢ (∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐵) ↔ ∀𝑥(𝑥 ∈ (𝐴 ∪ 𝐵) ↔ 𝑥 ∈ 𝐵)) |
7 | dfss2 3591 | . 2 ⊢ (𝐴 ⊆ 𝐵 ↔ ∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐵)) | |
8 | dfcleq 2616 | . 2 ⊢ ((𝐴 ∪ 𝐵) = 𝐵 ↔ ∀𝑥(𝑥 ∈ (𝐴 ∪ 𝐵) ↔ 𝑥 ∈ 𝐵)) | |
9 | 6, 7, 8 | 3bitr4i 292 | 1 ⊢ (𝐴 ⊆ 𝐵 ↔ (𝐴 ∪ 𝐵) = 𝐵) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 196 ∨ wo 383 ∀wal 1481 = wceq 1483 ∈ wcel 1990 ∪ cun 3572 ⊆ wss 3574 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1722 ax-4 1737 ax-5 1839 ax-6 1888 ax-7 1935 ax-9 1999 ax-10 2019 ax-11 2034 ax-12 2047 ax-13 2246 ax-ext 2602 |
This theorem depends on definitions: df-bi 197 df-or 385 df-an 386 df-tru 1486 df-ex 1705 df-nf 1710 df-sb 1881 df-clab 2609 df-cleq 2615 df-clel 2618 df-nfc 2753 df-v 3202 df-un 3579 df-in 3581 df-ss 3588 |
This theorem is referenced by: ssequn2 3786 undif 4049 uniop 4977 pwssun 5020 unisuc 5801 ordssun 5827 ordequn 5828 onun2i 5843 funiunfv 6506 sorpssun 6944 ordunpr 7026 onuninsuci 7040 domss2 8119 sucdom2 8156 findcard2s 8201 rankopb 8715 ranksuc 8728 kmlem11 8982 fin1a2lem10 9231 trclublem 13734 trclubi 13735 trclubiOLD 13736 trclub 13739 reltrclfv 13758 modfsummods 14525 cvgcmpce 14550 mreexexlem3d 16306 dprd2da 18441 dpjcntz 18451 dpjdisj 18452 dpjlsm 18453 dpjidcl 18457 ablfac1eu 18472 perfcls 21169 dfconn2 21222 comppfsc 21335 llycmpkgen2 21353 trfil2 21691 fixufil 21726 tsmsres 21947 ustssco 22018 ustuqtop1 22045 xrge0gsumle 22636 volsup 23324 mbfss 23413 itg2cnlem2 23529 iblss2 23572 vieta1lem2 24066 amgm 24717 wilthlem2 24795 ftalem3 24801 rpvmasum2 25201 iuninc 29379 hgt750lemb 30734 rankaltopb 32086 hfun 32285 nacsfix 37275 fvnonrel 37903 rclexi 37922 rtrclex 37924 trclubgNEW 37925 trclubNEW 37926 dfrtrcl5 37936 trrelsuperrel2dg 37963 iunrelexp0 37994 corcltrcl 38031 isotone1 38346 aacllem 42547 |
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