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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 3500 | . . . 4 ⊢ 𝑥 ∈ V | |
2 | 1 | elint 4885 | . . 3 ⊢ (𝑥 ∈ ∩ 𝐵 ↔ ∀𝑦(𝑦 ∈ 𝐵 → 𝑥 ∈ 𝑦)) |
3 | eleq1 2903 | . . . . . 6 ⊢ (𝑦 = 𝐴 → (𝑦 ∈ 𝐵 ↔ 𝐴 ∈ 𝐵)) | |
4 | eleq2 2904 | . . . . . 6 ⊢ (𝑦 = 𝐴 → (𝑥 ∈ 𝑦 ↔ 𝑥 ∈ 𝐴)) | |
5 | 3, 4 | imbi12d 347 | . . . . 5 ⊢ (𝑦 = 𝐴 → ((𝑦 ∈ 𝐵 → 𝑥 ∈ 𝑦) ↔ (𝐴 ∈ 𝐵 → 𝑥 ∈ 𝐴))) |
6 | 5 | spcgv 3598 | . . . 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 | syl5bi 244 | . 2 ⊢ (𝐴 ∈ 𝐵 → (𝑥 ∈ ∩ 𝐵 → 𝑥 ∈ 𝐴)) |
9 | 8 | ssrdv 3976 | 1 ⊢ (𝐴 ∈ 𝐵 → ∩ 𝐵 ⊆ 𝐴) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∀wal 1534 = wceq 1536 ∈ wcel 2113 ⊆ wss 3939 ∩ cint 4879 |
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 1910 ax-6 1969 ax-7 2014 ax-8 2115 ax-9 2123 ax-10 2144 ax-11 2160 ax-12 2176 ax-ext 2796 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-tru 1539 df-ex 1780 df-nf 1784 df-sb 2069 df-clab 2803 df-cleq 2817 df-clel 2896 df-nfc 2966 df-v 3499 df-in 3946 df-ss 3955 df-int 4880 |
This theorem is referenced by: intminss 4905 intmin3 4907 intab 4909 int0el 4910 trintss 5192 intex 5243 oneqmini 6245 sorpssint 7462 onint 7513 onssmin 7515 onnmin 7521 nnawordex 8266 dffi2 8890 inficl 8892 dffi3 8898 tcmin 9186 tc2 9187 rankr1ai 9230 rankuni2b 9285 tcrank 9316 harval2 9429 cfflb 9684 fin23lem20 9762 fin23lem38 9774 isf32lem2 9779 intwun 10160 inttsk 10199 intgru 10239 dfnn2 11654 dfuzi 12076 trclubi 14359 trclubgi 14360 trclub 14361 trclubg 14362 cotrtrclfv 14375 trclun 14377 dfrtrcl2 14424 mremre 16878 isacs1i 16931 mrelatglb 17797 cycsubg 18354 efgrelexlemb 18879 efgcpbllemb 18884 frgpuplem 18901 primefld 19587 cssmre 20840 toponmre 21704 1stcfb 22056 ptcnplem 22232 fbssfi 22448 uffix 22532 ufildom1 22537 alexsublem 22655 alexsubALTlem4 22661 tmdgsum2 22707 bcth3 23937 limciun 24495 aalioulem3 24926 shintcli 29109 shsval2i 29167 ococin 29188 chsupsn 29193 insiga 31400 ldsysgenld 31423 ldgenpisyslem2 31427 mclsssvlem 32813 mclsax 32820 mclsind 32821 untint 32942 dfon2lem8 33039 dfon2lem9 33040 sltval2 33167 sltres 33173 nocvxminlem 33251 scutun12 33275 scutbdaybnd 33279 scutbdaylt 33280 clsint2 33681 topmeet 33716 topjoin 33717 heibor1lem 35091 ismrcd1 39301 mzpincl 39337 mzpf 39339 mzpindd 39349 rgspnmin 39777 clublem 39976 dftrcl3 40071 brtrclfv2 40078 dfrtrcl3 40084 intsaluni 42619 intsal 42620 salgenss 42626 salgencntex 42633 |
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