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Mirrors > Home > MPE Home > Th. List > hashprb | Structured version Visualization version GIF version |
Description: The size of an unordered pair is 2 if and only if its elements are different sets. (Contributed by Alexander van der Vekens, 17-Jan-2018.) |
Ref | Expression |
---|---|
hashprb | ⊢ ((𝑀 ∈ V ∧ 𝑁 ∈ V ∧ 𝑀 ≠ 𝑁) ↔ (♯‘{𝑀, 𝑁}) = 2) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | hashprg 13759 | . . 3 ⊢ ((𝑀 ∈ V ∧ 𝑁 ∈ V) → (𝑀 ≠ 𝑁 ↔ (♯‘{𝑀, 𝑁}) = 2)) | |
2 | 1 | biimp3a 1465 | . 2 ⊢ ((𝑀 ∈ V ∧ 𝑁 ∈ V ∧ 𝑀 ≠ 𝑁) → (♯‘{𝑀, 𝑁}) = 2) |
3 | elprchashprn2 13760 | . . . 4 ⊢ (¬ 𝑀 ∈ V → ¬ (♯‘{𝑀, 𝑁}) = 2) | |
4 | pm2.21 123 | . . . 4 ⊢ (¬ (♯‘{𝑀, 𝑁}) = 2 → ((♯‘{𝑀, 𝑁}) = 2 → (𝑀 ∈ V ∧ 𝑁 ∈ V ∧ 𝑀 ≠ 𝑁))) | |
5 | 3, 4 | syl 17 | . . 3 ⊢ (¬ 𝑀 ∈ V → ((♯‘{𝑀, 𝑁}) = 2 → (𝑀 ∈ V ∧ 𝑁 ∈ V ∧ 𝑀 ≠ 𝑁))) |
6 | elprchashprn2 13760 | . . . 4 ⊢ (¬ 𝑁 ∈ V → ¬ (♯‘{𝑁, 𝑀}) = 2) | |
7 | prcom 4670 | . . . . . . 7 ⊢ {𝑁, 𝑀} = {𝑀, 𝑁} | |
8 | 7 | fveq2i 6675 | . . . . . 6 ⊢ (♯‘{𝑁, 𝑀}) = (♯‘{𝑀, 𝑁}) |
9 | 8 | eqeq1i 2828 | . . . . 5 ⊢ ((♯‘{𝑁, 𝑀}) = 2 ↔ (♯‘{𝑀, 𝑁}) = 2) |
10 | 9, 4 | sylnbi 332 | . . . 4 ⊢ (¬ (♯‘{𝑁, 𝑀}) = 2 → ((♯‘{𝑀, 𝑁}) = 2 → (𝑀 ∈ V ∧ 𝑁 ∈ V ∧ 𝑀 ≠ 𝑁))) |
11 | 6, 10 | syl 17 | . . 3 ⊢ (¬ 𝑁 ∈ V → ((♯‘{𝑀, 𝑁}) = 2 → (𝑀 ∈ V ∧ 𝑁 ∈ V ∧ 𝑀 ≠ 𝑁))) |
12 | simpll 765 | . . . . 5 ⊢ (((𝑀 ∈ V ∧ 𝑁 ∈ V) ∧ (♯‘{𝑀, 𝑁}) = 2) → 𝑀 ∈ V) | |
13 | simplr 767 | . . . . 5 ⊢ (((𝑀 ∈ V ∧ 𝑁 ∈ V) ∧ (♯‘{𝑀, 𝑁}) = 2) → 𝑁 ∈ V) | |
14 | 1 | biimpar 480 | . . . . 5 ⊢ (((𝑀 ∈ V ∧ 𝑁 ∈ V) ∧ (♯‘{𝑀, 𝑁}) = 2) → 𝑀 ≠ 𝑁) |
15 | 12, 13, 14 | 3jca 1124 | . . . 4 ⊢ (((𝑀 ∈ V ∧ 𝑁 ∈ V) ∧ (♯‘{𝑀, 𝑁}) = 2) → (𝑀 ∈ V ∧ 𝑁 ∈ V ∧ 𝑀 ≠ 𝑁)) |
16 | 15 | ex 415 | . . 3 ⊢ ((𝑀 ∈ V ∧ 𝑁 ∈ V) → ((♯‘{𝑀, 𝑁}) = 2 → (𝑀 ∈ V ∧ 𝑁 ∈ V ∧ 𝑀 ≠ 𝑁))) |
17 | 5, 11, 16 | ecase 1028 | . 2 ⊢ ((♯‘{𝑀, 𝑁}) = 2 → (𝑀 ∈ V ∧ 𝑁 ∈ V ∧ 𝑀 ≠ 𝑁)) |
18 | 2, 17 | impbii 211 | 1 ⊢ ((𝑀 ∈ V ∧ 𝑁 ∈ V ∧ 𝑀 ≠ 𝑁) ↔ (♯‘{𝑀, 𝑁}) = 2) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ↔ wb 208 ∧ wa 398 ∧ w3a 1083 = wceq 1537 ∈ wcel 2114 ≠ wne 3018 Vcvv 3496 {cpr 4571 ‘cfv 6357 2c2 11695 ♯chash 13693 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1796 ax-4 1810 ax-5 1911 ax-6 1970 ax-7 2015 ax-8 2116 ax-9 2124 ax-10 2145 ax-11 2161 ax-12 2177 ax-ext 2795 ax-rep 5192 ax-sep 5205 ax-nul 5212 ax-pow 5268 ax-pr 5332 ax-un 7463 ax-cnex 10595 ax-resscn 10596 ax-1cn 10597 ax-icn 10598 ax-addcl 10599 ax-addrcl 10600 ax-mulcl 10601 ax-mulrcl 10602 ax-mulcom 10603 ax-addass 10604 ax-mulass 10605 ax-distr 10606 ax-i2m1 10607 ax-1ne0 10608 ax-1rid 10609 ax-rnegex 10610 ax-rrecex 10611 ax-cnre 10612 ax-pre-lttri 10613 ax-pre-lttrn 10614 ax-pre-ltadd 10615 ax-pre-mulgt0 10616 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-3or 1084 df-3an 1085 df-tru 1540 df-ex 1781 df-nf 1785 df-sb 2070 df-mo 2622 df-eu 2654 df-clab 2802 df-cleq 2816 df-clel 2895 df-nfc 2965 df-ne 3019 df-nel 3126 df-ral 3145 df-rex 3146 df-reu 3147 df-rmo 3148 df-rab 3149 df-v 3498 df-sbc 3775 df-csb 3886 df-dif 3941 df-un 3943 df-in 3945 df-ss 3954 df-pss 3956 df-nul 4294 df-if 4470 df-pw 4543 df-sn 4570 df-pr 4572 df-tp 4574 df-op 4576 df-uni 4841 df-int 4879 df-iun 4923 df-br 5069 df-opab 5131 df-mpt 5149 df-tr 5175 df-id 5462 df-eprel 5467 df-po 5476 df-so 5477 df-fr 5516 df-we 5518 df-xp 5563 df-rel 5564 df-cnv 5565 df-co 5566 df-dm 5567 df-rn 5568 df-res 5569 df-ima 5570 df-pred 6150 df-ord 6196 df-on 6197 df-lim 6198 df-suc 6199 df-iota 6316 df-fun 6359 df-fn 6360 df-f 6361 df-f1 6362 df-fo 6363 df-f1o 6364 df-fv 6365 df-riota 7116 df-ov 7161 df-oprab 7162 df-mpo 7163 df-om 7583 df-1st 7691 df-2nd 7692 df-wrecs 7949 df-recs 8010 df-rdg 8048 df-1o 8104 df-oadd 8108 df-er 8291 df-en 8512 df-dom 8513 df-sdom 8514 df-fin 8515 df-dju 9332 df-card 9370 df-pnf 10679 df-mnf 10680 df-xr 10681 df-ltxr 10682 df-le 10683 df-sub 10874 df-neg 10875 df-nn 11641 df-2 11703 df-n0 11901 df-z 11985 df-uz 12247 df-fz 12896 df-hash 13694 |
This theorem is referenced by: hashprdifel 13762 prsshashgt1 13774 efmnd2hash 18061 symg2hash 18522 cplgr2vpr 27217 |
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