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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 4647 | . . . . . 6 ⊢ (𝑥 ∈ {𝐴} → 𝑥 = 𝐴) | |
2 | elsni 4647 | . . . . . 6 ⊢ (𝑦 ∈ {𝐴} → 𝑦 = 𝐴) | |
3 | 1, 2 | ineqan12d 4229 | . . . . 5 ⊢ ((𝑥 ∈ {𝐴} ∧ 𝑦 ∈ {𝐴}) → (𝑥 ∩ 𝑦) = (𝐴 ∩ 𝐴)) |
4 | inidm 4234 | . . . . 5 ⊢ (𝐴 ∩ 𝐴) = 𝐴 | |
5 | 3, 4 | eqtrdi 2790 | . . . 4 ⊢ ((𝑥 ∈ {𝐴} ∧ 𝑦 ∈ {𝐴}) → (𝑥 ∩ 𝑦) = 𝐴) |
6 | vex 3481 | . . . . . 6 ⊢ 𝑥 ∈ V | |
7 | 6 | inex1 5322 | . . . . 5 ⊢ (𝑥 ∩ 𝑦) ∈ V |
8 | 7 | elsn 4645 | . . . 4 ⊢ ((𝑥 ∩ 𝑦) ∈ {𝐴} ↔ (𝑥 ∩ 𝑦) = 𝐴) |
9 | 5, 8 | sylibr 234 | . . 3 ⊢ ((𝑥 ∈ {𝐴} ∧ 𝑦 ∈ {𝐴}) → (𝑥 ∩ 𝑦) ∈ {𝐴}) |
10 | 9 | rgen2 3196 | . 2 ⊢ ∀𝑥 ∈ {𝐴}∀𝑦 ∈ {𝐴} (𝑥 ∩ 𝑦) ∈ {𝐴} |
11 | snex 5441 | . . 3 ⊢ {𝐴} ∈ V | |
12 | inficl 9462 | . . 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 230 | 1 ⊢ (fi‘{𝐴}) = {𝐴} |
Colors of variables: wff setvar class |
Syntax hints: ↔ wb 206 ∧ wa 395 = wceq 1536 ∈ wcel 2105 ∀wral 3058 Vcvv 3477 ∩ cin 3961 {csn 4630 ‘cfv 6562 ficfi 9447 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1791 ax-4 1805 ax-5 1907 ax-6 1964 ax-7 2004 ax-8 2107 ax-9 2115 ax-10 2138 ax-11 2154 ax-12 2174 ax-ext 2705 ax-sep 5301 ax-nul 5311 ax-pow 5370 ax-pr 5437 ax-un 7753 |
This theorem depends on definitions: df-bi 207 df-an 396 df-or 848 df-3or 1087 df-3an 1088 df-tru 1539 df-fal 1549 df-ex 1776 df-nf 1780 df-sb 2062 df-mo 2537 df-eu 2566 df-clab 2712 df-cleq 2726 df-clel 2813 df-nfc 2889 df-ne 2938 df-ral 3059 df-rex 3068 df-reu 3378 df-rab 3433 df-v 3479 df-sbc 3791 df-dif 3965 df-un 3967 df-in 3969 df-ss 3979 df-pss 3982 df-nul 4339 df-if 4531 df-pw 4606 df-sn 4631 df-pr 4633 df-op 4637 df-uni 4912 df-int 4951 df-br 5148 df-opab 5210 df-mpt 5231 df-tr 5265 df-id 5582 df-eprel 5588 df-po 5596 df-so 5597 df-fr 5640 df-we 5642 df-xp 5694 df-rel 5695 df-cnv 5696 df-co 5697 df-dm 5698 df-rn 5699 df-res 5700 df-ima 5701 df-ord 6388 df-on 6389 df-lim 6390 df-suc 6391 df-iota 6515 df-fun 6564 df-fn 6565 df-f 6566 df-f1 6567 df-fo 6568 df-f1o 6569 df-fv 6570 df-om 7887 df-1o 8504 df-2o 8505 df-en 8984 df-fin 8987 df-fi 9448 |
This theorem is referenced by: ordtbas 23215 |
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