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Mirrors > Home > MPE Home > Th. List > en2eqpr | Structured version Visualization version GIF version |
Description: Building a set with two elements. (Contributed by FL, 11-Aug-2008.) (Revised by Mario Carneiro, 10-Sep-2015.) |
Ref | Expression |
---|---|
en2eqpr | ⊢ ((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) → (𝐴 ≠ 𝐵 → 𝐶 = {𝐴, 𝐵})) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 2onn 7987 | . . . . . 6 ⊢ 2o ∈ ω | |
2 | nnfi 8422 | . . . . . 6 ⊢ (2o ∈ ω → 2o ∈ Fin) | |
3 | 1, 2 | ax-mp 5 | . . . . 5 ⊢ 2o ∈ Fin |
4 | simpl1 1248 | . . . . 5 ⊢ (((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → 𝐶 ≈ 2o) | |
5 | enfii 8446 | . . . . 5 ⊢ ((2o ∈ Fin ∧ 𝐶 ≈ 2o) → 𝐶 ∈ Fin) | |
6 | 3, 4, 5 | sylancr 583 | . . . 4 ⊢ (((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → 𝐶 ∈ Fin) |
7 | simpl2 1250 | . . . . 5 ⊢ (((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → 𝐴 ∈ 𝐶) | |
8 | simpl3 1252 | . . . . 5 ⊢ (((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → 𝐵 ∈ 𝐶) | |
9 | prssi 4570 | . . . . 5 ⊢ ((𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) → {𝐴, 𝐵} ⊆ 𝐶) | |
10 | 7, 8, 9 | syl2anc 581 | . . . 4 ⊢ (((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → {𝐴, 𝐵} ⊆ 𝐶) |
11 | pr2nelem 9140 | . . . . . . 7 ⊢ ((𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶 ∧ 𝐴 ≠ 𝐵) → {𝐴, 𝐵} ≈ 2o) | |
12 | 11 | 3expa 1153 | . . . . . 6 ⊢ (((𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → {𝐴, 𝐵} ≈ 2o) |
13 | 12 | 3adantl1 1213 | . . . . 5 ⊢ (((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → {𝐴, 𝐵} ≈ 2o) |
14 | 4 | ensymd 8273 | . . . . 5 ⊢ (((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → 2o ≈ 𝐶) |
15 | entr 8274 | . . . . 5 ⊢ (({𝐴, 𝐵} ≈ 2o ∧ 2o ≈ 𝐶) → {𝐴, 𝐵} ≈ 𝐶) | |
16 | 13, 14, 15 | syl2anc 581 | . . . 4 ⊢ (((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → {𝐴, 𝐵} ≈ 𝐶) |
17 | fisseneq 8440 | . . . 4 ⊢ ((𝐶 ∈ Fin ∧ {𝐴, 𝐵} ⊆ 𝐶 ∧ {𝐴, 𝐵} ≈ 𝐶) → {𝐴, 𝐵} = 𝐶) | |
18 | 6, 10, 16, 17 | syl3anc 1496 | . . 3 ⊢ (((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → {𝐴, 𝐵} = 𝐶) |
19 | 18 | eqcomd 2831 | . 2 ⊢ (((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → 𝐶 = {𝐴, 𝐵}) |
20 | 19 | ex 403 | 1 ⊢ ((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) → (𝐴 ≠ 𝐵 → 𝐶 = {𝐴, 𝐵})) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 386 ∧ w3a 1113 = wceq 1658 ∈ wcel 2166 ≠ wne 2999 ⊆ wss 3798 {cpr 4399 class class class wbr 4873 ωcom 7326 2oc2o 7820 ≈ cen 8219 Fincfn 8222 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1896 ax-4 1910 ax-5 2011 ax-6 2077 ax-7 2114 ax-8 2168 ax-9 2175 ax-10 2194 ax-11 2209 ax-12 2222 ax-13 2391 ax-ext 2803 ax-sep 5005 ax-nul 5013 ax-pow 5065 ax-pr 5127 ax-un 7209 |
This theorem depends on definitions: df-bi 199 df-an 387 df-or 881 df-3or 1114 df-3an 1115 df-tru 1662 df-ex 1881 df-nf 1885 df-sb 2070 df-mo 2605 df-eu 2640 df-clab 2812 df-cleq 2818 df-clel 2821 df-nfc 2958 df-ne 3000 df-ral 3122 df-rex 3123 df-reu 3124 df-rab 3126 df-v 3416 df-sbc 3663 df-dif 3801 df-un 3803 df-in 3805 df-ss 3812 df-pss 3814 df-nul 4145 df-if 4307 df-pw 4380 df-sn 4398 df-pr 4400 df-tp 4402 df-op 4404 df-uni 4659 df-br 4874 df-opab 4936 df-tr 4976 df-id 5250 df-eprel 5255 df-po 5263 df-so 5264 df-fr 5301 df-we 5303 df-xp 5348 df-rel 5349 df-cnv 5350 df-co 5351 df-dm 5352 df-rn 5353 df-res 5354 df-ima 5355 df-ord 5966 df-on 5967 df-lim 5968 df-suc 5969 df-iota 6086 df-fun 6125 df-fn 6126 df-f 6127 df-f1 6128 df-fo 6129 df-f1o 6130 df-fv 6131 df-om 7327 df-1o 7826 df-2o 7827 df-er 8009 df-en 8223 df-dom 8224 df-sdom 8225 df-fin 8226 |
This theorem is referenced by: isprm2lem 15766 en2top 21160 |
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