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Mirrors > Home > MPE Home > Th. List > dfss2 | Structured version Visualization version GIF version |
Description: Alternate definition of the subclass relationship between two classes. Definition 5.9 of [TakeutiZaring] p. 17. (Contributed by NM, 8-Jan-2002.) Avoid ax-10 2142, ax-11 2158, ax-12 2175. (Revised by SN, 16-May-2024.) |
Ref | Expression |
---|---|
dfss2 | ⊢ (𝐴 ⊆ 𝐵 ↔ ∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐵)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | dfcleq 2792 | . 2 ⊢ (𝐴 = (𝐴 ∩ 𝐵) ↔ ∀𝑥(𝑥 ∈ 𝐴 ↔ 𝑥 ∈ (𝐴 ∩ 𝐵))) | |
2 | dfss 3899 | . 2 ⊢ (𝐴 ⊆ 𝐵 ↔ 𝐴 = (𝐴 ∩ 𝐵)) | |
3 | pm4.71 561 | . . . 4 ⊢ ((𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐵) ↔ (𝑥 ∈ 𝐴 ↔ (𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐵))) | |
4 | elin 3897 | . . . . 5 ⊢ (𝑥 ∈ (𝐴 ∩ 𝐵) ↔ (𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐵)) | |
5 | 4 | bibi2i 341 | . . . 4 ⊢ ((𝑥 ∈ 𝐴 ↔ 𝑥 ∈ (𝐴 ∩ 𝐵)) ↔ (𝑥 ∈ 𝐴 ↔ (𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐵))) |
6 | 3, 5 | bitr4i 281 | . . 3 ⊢ ((𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐵) ↔ (𝑥 ∈ 𝐴 ↔ 𝑥 ∈ (𝐴 ∩ 𝐵))) |
7 | 6 | albii 1821 | . 2 ⊢ (∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐵) ↔ ∀𝑥(𝑥 ∈ 𝐴 ↔ 𝑥 ∈ (𝐴 ∩ 𝐵))) |
8 | 1, 2, 7 | 3bitr4i 306 | 1 ⊢ (𝐴 ⊆ 𝐵 ↔ ∀𝑥(𝑥 ∈ 𝐴 → 𝑥 ∈ 𝐵)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 209 ∧ wa 399 ∀wal 1536 = wceq 1538 ∈ wcel 2111 ∩ cin 3880 ⊆ wss 3881 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1797 ax-4 1811 ax-5 1911 ax-6 1970 ax-7 2015 ax-8 2113 ax-9 2121 ax-ext 2770 |
This theorem depends on definitions: df-bi 210 df-an 400 df-ex 1782 df-sb 2070 df-clab 2777 df-cleq 2791 df-clel 2870 df-v 3443 df-in 3888 df-ss 3898 |
This theorem is referenced by: dfss3 3903 dfss6 3904 dfss2f 3905 ssel 3908 sselOLD 3909 ssriv 3919 ssrdv 3921 sstr2 3922 eqss 3930 nss 3977 rabss2 4005 ssconb 4065 ssequn1 4107 unss 4111 ssin 4157 ssdif0 4277 difin0ss 4282 inssdif0 4283 reldisj 4359 reldisjOLD 4360 ssundif 4391 sbcssg 4421 pwss 4522 snssg 4678 pwpw0 4706 pwsnOLD 4793 ssuni 4825 unissb 4832 iunssf 4931 iunss 4932 dftr2 5138 axpweq 5230 axpow2 5233 ssextss 5311 ssrel 5621 ssrel2 5623 ssrelrel 5633 reliun 5653 relop 5685 idrefALT 5940 funimass4 6705 dfom2 7562 inf2 9070 grothprim 10245 psslinpr 10442 ltaddpr 10445 isprm2 16016 vdwmc2 16305 acsmapd 17780 dfconn2 22024 iskgen3 22154 metcld 23910 metcld2 23911 isch2 29006 pjnormssi 29951 ssiun3 30322 ssrelf 30379 bnj1361 32210 bnj978 32331 dffr5 33102 brsset 33463 sscoid 33487 relowlpssretop 34781 fvineqsneq 34829 rp-fakeinunass 40223 rababg 40273 ss2iundf 40360 dfhe3 40476 snhesn 40487 dffrege76 40640 ntrneiiso 40794 ntrneik2 40795 ntrneix2 40796 ntrneikb 40797 expanduniss 41001 ismnuprim 41002 onfrALTlem2 41252 trsspwALT 41524 trsspwALT2 41525 snssiALTVD 41533 snssiALT 41534 sstrALT2VD 41540 sstrALT2 41541 sbcssgVD 41589 onfrALTlem2VD 41595 sspwimp 41624 sspwimpVD 41625 sspwimpcf 41626 sspwimpcfVD 41627 sspwimpALT 41631 unisnALT 41632 icccncfext 42529 |
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