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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 8260 | . . . . . 6 ⊢ 2o ∈ ω | |
2 | nnfi 8705 | . . . . . 6 ⊢ (2o ∈ ω → 2o ∈ Fin) | |
3 | 1, 2 | ax-mp 5 | . . . . 5 ⊢ 2o ∈ Fin |
4 | simpl1 1187 | . . . . 5 ⊢ (((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → 𝐶 ≈ 2o) | |
5 | enfii 8729 | . . . . 5 ⊢ ((2o ∈ Fin ∧ 𝐶 ≈ 2o) → 𝐶 ∈ Fin) | |
6 | 3, 4, 5 | sylancr 589 | . . . 4 ⊢ (((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → 𝐶 ∈ Fin) |
7 | simpl2 1188 | . . . . 5 ⊢ (((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → 𝐴 ∈ 𝐶) | |
8 | simpl3 1189 | . . . . 5 ⊢ (((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → 𝐵 ∈ 𝐶) | |
9 | 7, 8 | prssd 4748 | . . . 4 ⊢ (((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → {𝐴, 𝐵} ⊆ 𝐶) |
10 | pr2nelem 9424 | . . . . . . 7 ⊢ ((𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶 ∧ 𝐴 ≠ 𝐵) → {𝐴, 𝐵} ≈ 2o) | |
11 | 10 | 3expa 1114 | . . . . . 6 ⊢ (((𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → {𝐴, 𝐵} ≈ 2o) |
12 | 11 | 3adantl1 1162 | . . . . 5 ⊢ (((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → {𝐴, 𝐵} ≈ 2o) |
13 | 4 | ensymd 8554 | . . . . 5 ⊢ (((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → 2o ≈ 𝐶) |
14 | entr 8555 | . . . . 5 ⊢ (({𝐴, 𝐵} ≈ 2o ∧ 2o ≈ 𝐶) → {𝐴, 𝐵} ≈ 𝐶) | |
15 | 12, 13, 14 | syl2anc 586 | . . . 4 ⊢ (((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → {𝐴, 𝐵} ≈ 𝐶) |
16 | fisseneq 8723 | . . . 4 ⊢ ((𝐶 ∈ Fin ∧ {𝐴, 𝐵} ⊆ 𝐶 ∧ {𝐴, 𝐵} ≈ 𝐶) → {𝐴, 𝐵} = 𝐶) | |
17 | 6, 9, 15, 16 | syl3anc 1367 | . . 3 ⊢ (((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → {𝐴, 𝐵} = 𝐶) |
18 | 17 | eqcomd 2827 | . 2 ⊢ (((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) ∧ 𝐴 ≠ 𝐵) → 𝐶 = {𝐴, 𝐵}) |
19 | 18 | ex 415 | 1 ⊢ ((𝐶 ≈ 2o ∧ 𝐴 ∈ 𝐶 ∧ 𝐵 ∈ 𝐶) → (𝐴 ≠ 𝐵 → 𝐶 = {𝐴, 𝐵})) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 398 ∧ w3a 1083 = wceq 1533 ∈ wcel 2110 ≠ wne 3016 ⊆ wss 3935 {cpr 4562 class class class wbr 5058 ωcom 7574 2oc2o 8090 ≈ cen 8500 Fincfn 8503 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1792 ax-4 1806 ax-5 1907 ax-6 1966 ax-7 2011 ax-8 2112 ax-9 2120 ax-10 2141 ax-11 2157 ax-12 2173 ax-ext 2793 ax-sep 5195 ax-nul 5202 ax-pow 5258 ax-pr 5321 ax-un 7455 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-3or 1084 df-3an 1085 df-tru 1536 df-ex 1777 df-nf 1781 df-sb 2066 df-mo 2618 df-eu 2650 df-clab 2800 df-cleq 2814 df-clel 2893 df-nfc 2963 df-ne 3017 df-ral 3143 df-rex 3144 df-reu 3145 df-rab 3147 df-v 3496 df-sbc 3772 df-dif 3938 df-un 3940 df-in 3942 df-ss 3951 df-pss 3953 df-nul 4291 df-if 4467 df-pw 4540 df-sn 4561 df-pr 4563 df-tp 4565 df-op 4567 df-uni 4832 df-br 5059 df-opab 5121 df-tr 5165 df-id 5454 df-eprel 5459 df-po 5468 df-so 5469 df-fr 5508 df-we 5510 df-xp 5555 df-rel 5556 df-cnv 5557 df-co 5558 df-dm 5559 df-rn 5560 df-res 5561 df-ima 5562 df-ord 6188 df-on 6189 df-lim 6190 df-suc 6191 df-iota 6308 df-fun 6351 df-fn 6352 df-f 6353 df-f1 6354 df-fo 6355 df-f1o 6356 df-fv 6357 df-om 7575 df-1o 8096 df-2o 8097 df-er 8283 df-en 8504 df-dom 8505 df-sdom 8506 df-fin 8507 |
This theorem is referenced by: isprm2lem 16019 en2top 21587 |
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