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Mirrors > Home > MPE Home > Th. List > fisn | Structured version Visualization version GIF version |
Description: A singleton is closed under finite intersections. (Contributed by Mario Carneiro, 3-Sep-2015.) |
Ref | Expression |
---|---|
fisn | ⊢ (fi‘{𝐴}) = {𝐴} |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | elsni 4574 | . . . . . 6 ⊢ (𝑥 ∈ {𝐴} → 𝑥 = 𝐴) | |
2 | elsni 4574 | . . . . . 6 ⊢ (𝑦 ∈ {𝐴} → 𝑦 = 𝐴) | |
3 | 1, 2 | ineqan12d 4188 | . . . . 5 ⊢ ((𝑥 ∈ {𝐴} ∧ 𝑦 ∈ {𝐴}) → (𝑥 ∩ 𝑦) = (𝐴 ∩ 𝐴)) |
4 | inidm 4192 | . . . . 5 ⊢ (𝐴 ∩ 𝐴) = 𝐴 | |
5 | 3, 4 | syl6eq 2869 | . . . 4 ⊢ ((𝑥 ∈ {𝐴} ∧ 𝑦 ∈ {𝐴}) → (𝑥 ∩ 𝑦) = 𝐴) |
6 | vex 3495 | . . . . . 6 ⊢ 𝑥 ∈ V | |
7 | 6 | inex1 5212 | . . . . 5 ⊢ (𝑥 ∩ 𝑦) ∈ V |
8 | 7 | elsn 4572 | . . . 4 ⊢ ((𝑥 ∩ 𝑦) ∈ {𝐴} ↔ (𝑥 ∩ 𝑦) = 𝐴) |
9 | 5, 8 | sylibr 235 | . . 3 ⊢ ((𝑥 ∈ {𝐴} ∧ 𝑦 ∈ {𝐴}) → (𝑥 ∩ 𝑦) ∈ {𝐴}) |
10 | 9 | rgen2 3200 | . 2 ⊢ ∀𝑥 ∈ {𝐴}∀𝑦 ∈ {𝐴} (𝑥 ∩ 𝑦) ∈ {𝐴} |
11 | snex 5322 | . . 3 ⊢ {𝐴} ∈ V | |
12 | inficl 8877 | . . 3 ⊢ ({𝐴} ∈ V → (∀𝑥 ∈ {𝐴}∀𝑦 ∈ {𝐴} (𝑥 ∩ 𝑦) ∈ {𝐴} ↔ (fi‘{𝐴}) = {𝐴})) | |
13 | 11, 12 | ax-mp 5 | . 2 ⊢ (∀𝑥 ∈ {𝐴}∀𝑦 ∈ {𝐴} (𝑥 ∩ 𝑦) ∈ {𝐴} ↔ (fi‘{𝐴}) = {𝐴}) |
14 | 10, 13 | mpbi 231 | 1 ⊢ (fi‘{𝐴}) = {𝐴} |
Colors of variables: wff setvar class |
Syntax hints: ↔ wb 207 ∧ wa 396 = wceq 1528 ∈ wcel 2105 ∀wral 3135 Vcvv 3492 ∩ cin 3932 {csn 4557 ‘cfv 6348 ficfi 8862 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1787 ax-4 1801 ax-5 1902 ax-6 1961 ax-7 2006 ax-8 2107 ax-9 2115 ax-10 2136 ax-11 2151 ax-12 2167 ax-ext 2790 ax-sep 5194 ax-nul 5201 ax-pow 5257 ax-pr 5320 ax-un 7450 |
This theorem depends on definitions: df-bi 208 df-an 397 df-or 842 df-3or 1080 df-3an 1081 df-tru 1531 df-ex 1772 df-nf 1776 df-sb 2061 df-mo 2615 df-eu 2647 df-clab 2797 df-cleq 2811 df-clel 2890 df-nfc 2960 df-ne 3014 df-ral 3140 df-rex 3141 df-reu 3142 df-rab 3144 df-v 3494 df-sbc 3770 df-csb 3881 df-dif 3936 df-un 3938 df-in 3940 df-ss 3949 df-pss 3951 df-nul 4289 df-if 4464 df-pw 4537 df-sn 4558 df-pr 4560 df-tp 4562 df-op 4564 df-uni 4831 df-int 4868 df-iun 4912 df-br 5058 df-opab 5120 df-mpt 5138 df-tr 5164 df-id 5453 df-eprel 5458 df-po 5467 df-so 5468 df-fr 5507 df-we 5509 df-xp 5554 df-rel 5555 df-cnv 5556 df-co 5557 df-dm 5558 df-rn 5559 df-res 5560 df-ima 5561 df-pred 6141 df-ord 6187 df-on 6188 df-lim 6189 df-suc 6190 df-iota 6307 df-fun 6350 df-fn 6351 df-f 6352 df-f1 6353 df-fo 6354 df-f1o 6355 df-fv 6356 df-ov 7148 df-oprab 7149 df-mpo 7150 df-om 7570 df-wrecs 7936 df-recs 7997 df-rdg 8035 df-1o 8091 df-oadd 8095 df-er 8278 df-en 8498 df-fin 8501 df-fi 8863 |
This theorem is referenced by: ordtbas 21728 |
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