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Mirrors > Home > MPE Home > Th. List > hash2prde | Structured version Visualization version GIF version |
Description: A set of size two is an unordered pair of two different elements. (Contributed by Alexander van der Vekens, 8-Dec-2017.) |
Ref | Expression |
---|---|
hash2prde | ⊢ ((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) → ∃𝑎∃𝑏(𝑎 ≠ 𝑏 ∧ 𝑉 = {𝑎, 𝑏})) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | hash2pr 14368 | . 2 ⊢ ((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) → ∃𝑎∃𝑏 𝑉 = {𝑎, 𝑏}) | |
2 | equid 2015 | . . . . . . 7 ⊢ 𝑏 = 𝑏 | |
3 | vex 3449 | . . . . . . . . 9 ⊢ 𝑎 ∈ V | |
4 | vex 3449 | . . . . . . . . 9 ⊢ 𝑏 ∈ V | |
5 | 3, 4 | preqsn 4819 | . . . . . . . 8 ⊢ ({𝑎, 𝑏} = {𝑏} ↔ (𝑎 = 𝑏 ∧ 𝑏 = 𝑏)) |
6 | eqeq2 2748 | . . . . . . . . . 10 ⊢ ({𝑎, 𝑏} = {𝑏} → (𝑉 = {𝑎, 𝑏} ↔ 𝑉 = {𝑏})) | |
7 | fveq2 6842 | . . . . . . . . . . . 12 ⊢ (𝑉 = {𝑏} → (♯‘𝑉) = (♯‘{𝑏})) | |
8 | hashsng 14269 | . . . . . . . . . . . . 13 ⊢ (𝑏 ∈ V → (♯‘{𝑏}) = 1) | |
9 | 8 | elv 3451 | . . . . . . . . . . . 12 ⊢ (♯‘{𝑏}) = 1 |
10 | 7, 9 | eqtrdi 2792 | . . . . . . . . . . 11 ⊢ (𝑉 = {𝑏} → (♯‘𝑉) = 1) |
11 | eqeq1 2740 | . . . . . . . . . . . . 13 ⊢ ((♯‘𝑉) = 2 → ((♯‘𝑉) = 1 ↔ 2 = 1)) | |
12 | 1ne2 12361 | . . . . . . . . . . . . . . 15 ⊢ 1 ≠ 2 | |
13 | df-ne 2944 | . . . . . . . . . . . . . . . 16 ⊢ (1 ≠ 2 ↔ ¬ 1 = 2) | |
14 | pm2.21 123 | . . . . . . . . . . . . . . . 16 ⊢ (¬ 1 = 2 → (1 = 2 → 𝑎 ≠ 𝑏)) | |
15 | 13, 14 | sylbi 216 | . . . . . . . . . . . . . . 15 ⊢ (1 ≠ 2 → (1 = 2 → 𝑎 ≠ 𝑏)) |
16 | 12, 15 | ax-mp 5 | . . . . . . . . . . . . . 14 ⊢ (1 = 2 → 𝑎 ≠ 𝑏) |
17 | 16 | eqcoms 2744 | . . . . . . . . . . . . 13 ⊢ (2 = 1 → 𝑎 ≠ 𝑏) |
18 | 11, 17 | syl6bi 252 | . . . . . . . . . . . 12 ⊢ ((♯‘𝑉) = 2 → ((♯‘𝑉) = 1 → 𝑎 ≠ 𝑏)) |
19 | 18 | adantl 482 | . . . . . . . . . . 11 ⊢ ((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) → ((♯‘𝑉) = 1 → 𝑎 ≠ 𝑏)) |
20 | 10, 19 | syl5com 31 | . . . . . . . . . 10 ⊢ (𝑉 = {𝑏} → ((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) → 𝑎 ≠ 𝑏)) |
21 | 6, 20 | syl6bi 252 | . . . . . . . . 9 ⊢ ({𝑎, 𝑏} = {𝑏} → (𝑉 = {𝑎, 𝑏} → ((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) → 𝑎 ≠ 𝑏))) |
22 | 21 | impcomd 412 | . . . . . . . 8 ⊢ ({𝑎, 𝑏} = {𝑏} → (((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) ∧ 𝑉 = {𝑎, 𝑏}) → 𝑎 ≠ 𝑏)) |
23 | 5, 22 | sylbir 234 | . . . . . . 7 ⊢ ((𝑎 = 𝑏 ∧ 𝑏 = 𝑏) → (((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) ∧ 𝑉 = {𝑎, 𝑏}) → 𝑎 ≠ 𝑏)) |
24 | 2, 23 | mpan2 689 | . . . . . 6 ⊢ (𝑎 = 𝑏 → (((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) ∧ 𝑉 = {𝑎, 𝑏}) → 𝑎 ≠ 𝑏)) |
25 | ax-1 6 | . . . . . 6 ⊢ (𝑎 ≠ 𝑏 → (((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) ∧ 𝑉 = {𝑎, 𝑏}) → 𝑎 ≠ 𝑏)) | |
26 | 24, 25 | pm2.61ine 3028 | . . . . 5 ⊢ (((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) ∧ 𝑉 = {𝑎, 𝑏}) → 𝑎 ≠ 𝑏) |
27 | simpr 485 | . . . . 5 ⊢ (((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) ∧ 𝑉 = {𝑎, 𝑏}) → 𝑉 = {𝑎, 𝑏}) | |
28 | 26, 27 | jca 512 | . . . 4 ⊢ (((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) ∧ 𝑉 = {𝑎, 𝑏}) → (𝑎 ≠ 𝑏 ∧ 𝑉 = {𝑎, 𝑏})) |
29 | 28 | ex 413 | . . 3 ⊢ ((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) → (𝑉 = {𝑎, 𝑏} → (𝑎 ≠ 𝑏 ∧ 𝑉 = {𝑎, 𝑏}))) |
30 | 29 | 2eximdv 1922 | . 2 ⊢ ((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) → (∃𝑎∃𝑏 𝑉 = {𝑎, 𝑏} → ∃𝑎∃𝑏(𝑎 ≠ 𝑏 ∧ 𝑉 = {𝑎, 𝑏}))) |
31 | 1, 30 | mpd 15 | 1 ⊢ ((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) → ∃𝑎∃𝑏(𝑎 ≠ 𝑏 ∧ 𝑉 = {𝑎, 𝑏})) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ∧ wa 396 = wceq 1541 ∃wex 1781 ∈ wcel 2106 ≠ wne 2943 Vcvv 3445 {csn 4586 {cpr 4588 ‘cfv 6496 1c1 11052 2c2 12208 ♯chash 14230 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1797 ax-4 1811 ax-5 1913 ax-6 1971 ax-7 2011 ax-8 2108 ax-9 2116 ax-10 2137 ax-11 2154 ax-12 2171 ax-ext 2707 ax-sep 5256 ax-nul 5263 ax-pow 5320 ax-pr 5384 ax-un 7672 ax-cnex 11107 ax-resscn 11108 ax-1cn 11109 ax-icn 11110 ax-addcl 11111 ax-addrcl 11112 ax-mulcl 11113 ax-mulrcl 11114 ax-mulcom 11115 ax-addass 11116 ax-mulass 11117 ax-distr 11118 ax-i2m1 11119 ax-1ne0 11120 ax-1rid 11121 ax-rnegex 11122 ax-rrecex 11123 ax-cnre 11124 ax-pre-lttri 11125 ax-pre-lttrn 11126 ax-pre-ltadd 11127 ax-pre-mulgt0 11128 |
This theorem depends on definitions: df-bi 206 df-an 397 df-or 846 df-3or 1088 df-3an 1089 df-tru 1544 df-fal 1554 df-ex 1782 df-nf 1786 df-sb 2068 df-mo 2538 df-eu 2567 df-clab 2714 df-cleq 2728 df-clel 2814 df-nfc 2889 df-ne 2944 df-nel 3050 df-ral 3065 df-rex 3074 df-reu 3354 df-rab 3408 df-v 3447 df-sbc 3740 df-csb 3856 df-dif 3913 df-un 3915 df-in 3917 df-ss 3927 df-pss 3929 df-nul 4283 df-if 4487 df-pw 4562 df-sn 4587 df-pr 4589 df-op 4593 df-uni 4866 df-int 4908 df-iun 4956 df-br 5106 df-opab 5168 df-mpt 5189 df-tr 5223 df-id 5531 df-eprel 5537 df-po 5545 df-so 5546 df-fr 5588 df-we 5590 df-xp 5639 df-rel 5640 df-cnv 5641 df-co 5642 df-dm 5643 df-rn 5644 df-res 5645 df-ima 5646 df-pred 6253 df-ord 6320 df-on 6321 df-lim 6322 df-suc 6323 df-iota 6448 df-fun 6498 df-fn 6499 df-f 6500 df-f1 6501 df-fo 6502 df-f1o 6503 df-fv 6504 df-riota 7313 df-ov 7360 df-oprab 7361 df-mpo 7362 df-om 7803 df-1st 7921 df-2nd 7922 df-frecs 8212 df-wrecs 8243 df-recs 8317 df-rdg 8356 df-1o 8412 df-2o 8413 df-oadd 8416 df-er 8648 df-en 8884 df-dom 8885 df-sdom 8886 df-fin 8887 df-dju 9837 df-card 9875 df-pnf 11191 df-mnf 11192 df-xr 11193 df-ltxr 11194 df-le 11195 df-sub 11387 df-neg 11388 df-nn 12154 df-2 12216 df-n0 12414 df-z 12500 df-uz 12764 df-fz 13425 df-hash 14231 |
This theorem is referenced by: hash2exprb 14370 umgredg 28089 frgrregord013 29339 |
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