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Mirrors > Home > MPE Home > Th. List > sstr2 | Structured version Visualization version GIF version |
Description: Transitivity of subclass relationship. Exercise 5 of [TakeutiZaring] p. 17. (Contributed by NM, 24-Jun-1993.) (Proof shortened by Andrew Salmon, 14-Jun-2011.) Avoid axioms. (Revised by GG, 19-May-2025.) |
Ref | Expression |
---|---|
sstr2 | ⊢ (𝐴 ⊆ 𝐵 → (𝐵 ⊆ 𝐶 → 𝐴 ⊆ 𝐶)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | imim1 83 | . . 3 ⊢ ((𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐵) → ((𝑥 ∈ 𝐵 → 𝑥 ∈ 𝐶) → (𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶))) | |
2 | 1 | al2imi 1811 | . 2 ⊢ (∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐵) → (∀𝑥(𝑥 ∈ 𝐵 → 𝑥 ∈ 𝐶) → ∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶))) |
3 | df-ss 3979 | . 2 ⊢ (𝐴 ⊆ 𝐵 ↔ ∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐵)) | |
4 | df-ss 3979 | . . 3 ⊢ (𝐵 ⊆ 𝐶 ↔ ∀𝑥(𝑥 ∈ 𝐵 → 𝑥 ∈ 𝐶)) | |
5 | df-ss 3979 | . . 3 ⊢ (𝐴 ⊆ 𝐶 ↔ ∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶)) | |
6 | 4, 5 | imbi12i 350 | . 2 ⊢ ((𝐵 ⊆ 𝐶 → 𝐴 ⊆ 𝐶) ↔ (∀𝑥(𝑥 ∈ 𝐵 → 𝑥 ∈ 𝐶) → ∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐶))) |
7 | 2, 3, 6 | 3imtr4i 292 | 1 ⊢ (𝐴 ⊆ 𝐵 → (𝐵 ⊆ 𝐶 → 𝐴 ⊆ 𝐶)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∀wal 1534 ∈ wcel 2105 ⊆ 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 |
This theorem depends on definitions: df-bi 207 df-ss 3979 |
This theorem is referenced by: sstr 4003 sstri 4004 sseq1 4020 sseq2 4021 ssun3 4189 ssun4 4190 ssinss1 4253 sspw 4615 triun 5279 trintss 5283 exss 5473 frss 5652 relss 5793 funss 6586 funimass2 6650 fss 6752 sucexeloniOLD 7829 suceloniOLD 7831 limsssuc 7870 oaordi 8582 oeworde 8629 nnaordi 8654 sbthlem2 9122 sbthlem3 9123 sbthlem6 9126 domunfican 9358 fiint 9363 fiintOLD 9364 fiss 9461 dffi3 9468 inf3lem1 9665 trcl 9765 tcss 9781 ac10ct 10071 ackbij2lem4 10278 cfslb 10303 cfslbn 10304 cfcoflem 10309 coftr 10310 fin23lem15 10371 fin23lem20 10374 fin23lem36 10385 isf32lem1 10390 axdc3lem2 10488 ttukeylem2 10547 wunex2 10775 tskcard 10818 clsslem 15019 mrcss 17660 isacs2 17697 lubss 18570 frmdss2 18888 lsmlub 19696 lsslss 20976 lspss 20999 ocv2ss 21708 ocvsscon 21710 lindsss 21861 lsslinds 21868 aspss 21914 mplcoe1 22072 mplcoe5 22075 mdetunilem9 22641 tgss 22990 tgcl 22991 tgss3 23008 clsss 23077 ntrss 23078 neiss 23132 ssnei2 23139 opnnei 23143 cnpnei 23287 cnpco 23290 cncls 23297 cnprest 23312 hauscmp 23430 1stcfb 23468 1stcelcls 23484 reftr 23537 txcnpi 23631 txcnp 23643 txtube 23663 qtoptop2 23722 fgcl 23901 filssufilg 23934 ufileu 23942 uffix 23944 elfm2 23971 fmfnfmlem1 23977 fmco 23984 fbflim2 24000 flffbas 24018 flftg 24019 cnpflf2 24023 alexsubALTlem4 24073 neibl 24529 metcnp3 24568 xlebnum 25010 lebnumii 25011 caubl 25355 caublcls 25356 bcthlem2 25372 bcthlem5 25375 ovolsslem 25532 volsuplem 25603 dyadmbllem 25647 ellimc3 25928 limciun 25943 cpnord 25985 precsexlem6 28250 precsexlem7 28251 ubthlem1 30898 occon3 31325 chsupval 31363 chsupcl 31368 chsupss 31370 spanss 31376 chsupval2 31438 stlei 32268 dmdbr5 32336 mdsl0 32338 chrelat2i 32393 chirredlem1 32418 mdsymlem5 32435 mdsymlem6 32436 gsumle 33083 gsumvsca1 33214 gsumvsca2 33215 omsmon 34279 cvmliftlem15 35282 ss2mcls 35552 mclsax 35553 clsint2 36311 fgmin 36352 filnetlem4 36363 limsucncmpi 36427 bj-restpw 37074 bj-0int 37083 rdgssun 37360 ptrecube 37606 heiborlem1 37797 heiborlem8 37804 refrelsredund4 38613 refrelredund4 38616 funALTVss 38680 pclssN 39876 dochexmidlem7 41448 incssnn0 42698 islssfg2 43059 hbtlem6 43117 hess 43769 psshepw 43777 clsf2 44115 mnuunid 44272 ismnushort 44296 sspwimpcf 44917 sspwimpcfVD 44918 dvmptfprod 45900 sprsymrelfo 47421 elbigo2 48401 subthinc 48839 setrec1lem2 48918 setrec1lem4 48920 setrec2mpt 48927 |
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