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Mirrors > Home > MPE Home > Th. List > intss1 | Structured version Visualization version GIF version |
Description: An element of a class includes the intersection of the class. Exercise 4 of [TakeutiZaring] p. 44 (with correction), generalized to classes. (Contributed by NM, 18-Nov-1995.) |
Ref | Expression |
---|---|
intss1 | ⊢ (𝐴 ∈ 𝐵 → ∩ 𝐵 ⊆ 𝐴) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | vex 3476 | . . . 4 ⊢ 𝑥 ∈ V | |
2 | 1 | elint 4957 | . . 3 ⊢ (𝑥 ∈ ∩ 𝐵 ↔ ∀𝑦(𝑦 ∈ 𝐵 → 𝑥 ∈ 𝑦)) |
3 | eleq1 2819 | . . . . . 6 ⊢ (𝑦 = 𝐴 → (𝑦 ∈ 𝐵 ↔ 𝐴 ∈ 𝐵)) | |
4 | eleq2 2820 | . . . . . 6 ⊢ (𝑦 = 𝐴 → (𝑥 ∈ 𝑦 ↔ 𝑥 ∈ 𝐴)) | |
5 | 3, 4 | imbi12d 343 | . . . . 5 ⊢ (𝑦 = 𝐴 → ((𝑦 ∈ 𝐵 → 𝑥 ∈ 𝑦) ↔ (𝐴 ∈ 𝐵 → 𝑥 ∈ 𝐴))) |
6 | 5 | spcgv 3587 | . . . 4 ⊢ (𝐴 ∈ 𝐵 → (∀𝑦(𝑦 ∈ 𝐵 → 𝑥 ∈ 𝑦) → (𝐴 ∈ 𝐵 → 𝑥 ∈ 𝐴))) |
7 | 6 | pm2.43a 54 | . . 3 ⊢ (𝐴 ∈ 𝐵 → (∀𝑦(𝑦 ∈ 𝐵 → 𝑥 ∈ 𝑦) → 𝑥 ∈ 𝐴)) |
8 | 2, 7 | biimtrid 241 | . 2 ⊢ (𝐴 ∈ 𝐵 → (𝑥 ∈ ∩ 𝐵 → 𝑥 ∈ 𝐴)) |
9 | 8 | ssrdv 3989 | 1 ⊢ (𝐴 ∈ 𝐵 → ∩ 𝐵 ⊆ 𝐴) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∀wal 1537 = wceq 1539 ∈ wcel 2104 ⊆ wss 3949 ∩ cint 4951 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1795 ax-4 1809 ax-5 1911 ax-6 1969 ax-7 2009 ax-8 2106 ax-9 2114 ax-ext 2701 |
This theorem depends on definitions: df-bi 206 df-an 395 df-tru 1542 df-ex 1780 df-sb 2066 df-clab 2708 df-cleq 2722 df-clel 2808 df-v 3474 df-in 3956 df-ss 3966 df-int 4952 |
This theorem is referenced by: intminss 4979 intmin3 4981 intab 4983 int0el 4984 trintss 5285 intex 5338 intidg 5458 oneqmini 6417 sorpssint 7727 onint 7782 onssmin 7784 onnmin 7790 nnawordex 8641 cofon1 8675 cofonr 8677 dffi2 9422 inficl 9424 dffi3 9430 tcmin 9740 tc2 9741 rankr1ai 9797 rankuni2b 9852 tcrank 9883 harval2 9996 cfflb 10258 fin23lem20 10336 fin23lem38 10348 isf32lem2 10353 intwun 10734 inttsk 10773 intgru 10813 dfnn2 12231 dfuzi 12659 trclubi 14949 trclubgi 14950 trclub 14951 trclubg 14952 cotrtrclfv 14965 trclun 14967 dfrtrcl2 15015 mremre 17554 isacs1i 17607 mrelatglb 18519 cycsubg 19125 efgrelexlemb 19661 efgcpbllemb 19666 frgpuplem 19683 primefld 20566 cssmre 21467 toponmre 22819 1stcfb 23171 ptcnplem 23347 fbssfi 23563 uffix 23647 ufildom1 23652 alexsublem 23770 alexsubALTlem4 23776 tmdgsum2 23822 bcth3 25081 limciun 25645 aalioulem3 26081 sltval2 27393 sltres 27399 nocvxminlem 27513 eqscut2 27542 scutun12 27546 scutbdaybnd 27551 scutbdaybnd2 27552 scutbdaylt 27554 madebdaylemlrcut 27628 cofcut1 27643 cofcutr 27647 dfn0s2 27939 shintcli 30847 shsval2i 30905 ococin 30926 chsupsn 30931 fldgensdrg 32672 fldgenssv 32673 fldgenssp 32676 insiga 33431 ldsysgenld 33454 ldgenpisyslem2 33458 mclsssvlem 34849 mclsax 34856 mclsind 34857 untint 34983 dfon2lem8 35064 dfon2lem9 35065 clsint2 35519 topmeet 35554 topjoin 35555 heibor1lem 36982 ismrcd1 41740 mzpincl 41776 mzpf 41778 mzpindd 41788 rgspnmin 42217 onintunirab 42280 oninfint 42289 clublem 42665 dftrcl3 42775 brtrclfv2 42782 dfrtrcl3 42788 intsaluni 45345 intsal 45346 salgenss 45352 salgencntex 45359 intubeu 47698 |
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