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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 13821 | . 2 ⊢ ((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) → ∃𝑎∃𝑏 𝑉 = {𝑎, 𝑏}) | |
2 | equid 2015 | . . . . . . 7 ⊢ 𝑏 = 𝑏 | |
3 | vex 3498 | . . . . . . . . 9 ⊢ 𝑎 ∈ V | |
4 | vex 3498 | . . . . . . . . 9 ⊢ 𝑏 ∈ V | |
5 | 3, 4 | preqsn 4786 | . . . . . . . 8 ⊢ ({𝑎, 𝑏} = {𝑏} ↔ (𝑎 = 𝑏 ∧ 𝑏 = 𝑏)) |
6 | eqeq2 2833 | . . . . . . . . . 10 ⊢ ({𝑎, 𝑏} = {𝑏} → (𝑉 = {𝑎, 𝑏} ↔ 𝑉 = {𝑏})) | |
7 | fveq2 6665 | . . . . . . . . . . . 12 ⊢ (𝑉 = {𝑏} → (♯‘𝑉) = (♯‘{𝑏})) | |
8 | hashsng 13724 | . . . . . . . . . . . . 13 ⊢ (𝑏 ∈ V → (♯‘{𝑏}) = 1) | |
9 | 8 | elv 3500 | . . . . . . . . . . . 12 ⊢ (♯‘{𝑏}) = 1 |
10 | 7, 9 | syl6eq 2872 | . . . . . . . . . . 11 ⊢ (𝑉 = {𝑏} → (♯‘𝑉) = 1) |
11 | eqeq1 2825 | . . . . . . . . . . . . 13 ⊢ ((♯‘𝑉) = 2 → ((♯‘𝑉) = 1 ↔ 2 = 1)) | |
12 | 1ne2 11839 | . . . . . . . . . . . . . . 15 ⊢ 1 ≠ 2 | |
13 | df-ne 3017 | . . . . . . . . . . . . . . . 16 ⊢ (1 ≠ 2 ↔ ¬ 1 = 2) | |
14 | pm2.21 123 | . . . . . . . . . . . . . . . 16 ⊢ (¬ 1 = 2 → (1 = 2 → 𝑎 ≠ 𝑏)) | |
15 | 13, 14 | sylbi 219 | . . . . . . . . . . . . . . 15 ⊢ (1 ≠ 2 → (1 = 2 → 𝑎 ≠ 𝑏)) |
16 | 12, 15 | ax-mp 5 | . . . . . . . . . . . . . 14 ⊢ (1 = 2 → 𝑎 ≠ 𝑏) |
17 | 16 | eqcoms 2829 | . . . . . . . . . . . . 13 ⊢ (2 = 1 → 𝑎 ≠ 𝑏) |
18 | 11, 17 | syl6bi 255 | . . . . . . . . . . . 12 ⊢ ((♯‘𝑉) = 2 → ((♯‘𝑉) = 1 → 𝑎 ≠ 𝑏)) |
19 | 18 | adantl 484 | . . . . . . . . . . 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 255 | . . . . . . . . 9 ⊢ ({𝑎, 𝑏} = {𝑏} → (𝑉 = {𝑎, 𝑏} → ((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) → 𝑎 ≠ 𝑏))) |
22 | 21 | impcomd 414 | . . . . . . . 8 ⊢ ({𝑎, 𝑏} = {𝑏} → (((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) ∧ 𝑉 = {𝑎, 𝑏}) → 𝑎 ≠ 𝑏)) |
23 | 5, 22 | sylbir 237 | . . . . . . 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 3100 | . . . . 5 ⊢ (((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) ∧ 𝑉 = {𝑎, 𝑏}) → 𝑎 ≠ 𝑏) |
27 | simpr 487 | . . . . 5 ⊢ (((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) ∧ 𝑉 = {𝑎, 𝑏}) → 𝑉 = {𝑎, 𝑏}) | |
28 | 26, 27 | jca 514 | . . . 4 ⊢ (((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) ∧ 𝑉 = {𝑎, 𝑏}) → (𝑎 ≠ 𝑏 ∧ 𝑉 = {𝑎, 𝑏})) |
29 | 28 | ex 415 | . . 3 ⊢ ((𝑉 ∈ 𝑊 ∧ (♯‘𝑉) = 2) → (𝑉 = {𝑎, 𝑏} → (𝑎 ≠ 𝑏 ∧ 𝑉 = {𝑎, 𝑏}))) |
30 | 29 | 2eximdv 1916 | . 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 398 = wceq 1533 ∃wex 1776 ∈ wcel 2110 ≠ wne 3016 Vcvv 3495 {csn 4561 {cpr 4563 ‘cfv 6350 1c1 10532 2c2 11686 ♯chash 13684 |
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 2156 ax-12 2172 ax-ext 2793 ax-rep 5183 ax-sep 5196 ax-nul 5203 ax-pow 5259 ax-pr 5322 ax-un 7455 ax-cnex 10587 ax-resscn 10588 ax-1cn 10589 ax-icn 10590 ax-addcl 10591 ax-addrcl 10592 ax-mulcl 10593 ax-mulrcl 10594 ax-mulcom 10595 ax-addass 10596 ax-mulass 10597 ax-distr 10598 ax-i2m1 10599 ax-1ne0 10600 ax-1rid 10601 ax-rnegex 10602 ax-rrecex 10603 ax-cnre 10604 ax-pre-lttri 10605 ax-pre-lttrn 10606 ax-pre-ltadd 10607 ax-pre-mulgt0 10608 |
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-nel 3124 df-ral 3143 df-rex 3144 df-reu 3145 df-rmo 3146 df-rab 3147 df-v 3497 df-sbc 3773 df-csb 3884 df-dif 3939 df-un 3941 df-in 3943 df-ss 3952 df-pss 3954 df-nul 4292 df-if 4468 df-pw 4541 df-sn 4562 df-pr 4564 df-tp 4566 df-op 4568 df-uni 4833 df-int 4870 df-iun 4914 df-br 5060 df-opab 5122 df-mpt 5140 df-tr 5166 df-id 5455 df-eprel 5460 df-po 5469 df-so 5470 df-fr 5509 df-we 5511 df-xp 5556 df-rel 5557 df-cnv 5558 df-co 5559 df-dm 5560 df-rn 5561 df-res 5562 df-ima 5563 df-pred 6143 df-ord 6189 df-on 6190 df-lim 6191 df-suc 6192 df-iota 6309 df-fun 6352 df-fn 6353 df-f 6354 df-f1 6355 df-fo 6356 df-f1o 6357 df-fv 6358 df-riota 7108 df-ov 7153 df-oprab 7154 df-mpo 7155 df-om 7575 df-1st 7683 df-2nd 7684 df-wrecs 7941 df-recs 8002 df-rdg 8040 df-1o 8096 df-2o 8097 df-oadd 8100 df-er 8283 df-en 8504 df-dom 8505 df-sdom 8506 df-fin 8507 df-dju 9324 df-card 9362 df-pnf 10671 df-mnf 10672 df-xr 10673 df-ltxr 10674 df-le 10675 df-sub 10866 df-neg 10867 df-nn 11633 df-2 11694 df-n0 11892 df-z 11976 df-uz 12238 df-fz 12887 df-hash 13685 |
This theorem is referenced by: hash2exprb 13823 umgredg 26917 frgrregord013 28168 |
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