hasheq0 - Metamath Proof Explorer

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Theorem hasheq0 14290

Description: Two ways of saying a set is empty. (Contributed by Paul Chapman, 26-Oct-2012.) (Revised by Mario Carneiro, 27-Jul-2014.)

**Assertion**
Ref	Expression
hasheq0	⊢ (𝐴 ∈ 𝑉 → ((♯‘𝐴) = 0 ↔ 𝐴 = ∅))

**Proof of Theorem hasheq0**
Step	Hyp	Ref	Expression
1		pnfnre 11177	. . . . . . 7 ⊢ +∞ ∉ ℝ
2	1	neli 3039	. . . . . 6 ⊢ ¬ +∞ ∈ ℝ
3		hashinf 14262	. . . . . . 7 ⊢ ((𝐴 ∈ 𝑉 ∧ ¬ 𝐴 ∈ Fin) → (♯‘𝐴) = +∞)
4	3	eleq1d 2822	. . . . . 6 ⊢ ((𝐴 ∈ 𝑉 ∧ ¬ 𝐴 ∈ Fin) → ((♯‘𝐴) ∈ ℝ ↔ +∞ ∈ ℝ))
5	2, 4	mtbiri 327	. . . . 5 ⊢ ((𝐴 ∈ 𝑉 ∧ ¬ 𝐴 ∈ Fin) → ¬ (♯‘𝐴) ∈ ℝ)
6		id 22	. . . . . 6 ⊢ ((♯‘𝐴) = 0 → (♯‘𝐴) = 0)
7		0re 11138	. . . . . 6 ⊢ 0 ∈ ℝ
8	6, 7	eqeltrdi 2845	. . . . 5 ⊢ ((♯‘𝐴) = 0 → (♯‘𝐴) ∈ ℝ)
9	5, 8	nsyl 140	. . . 4 ⊢ ((𝐴 ∈ 𝑉 ∧ ¬ 𝐴 ∈ Fin) → ¬ (♯‘𝐴) = 0)
10		id 22	. . . . . . 7 ⊢ (𝐴 = ∅ → 𝐴 = ∅)
11		0fi 8983	. . . . . . 7 ⊢ ∅ ∈ Fin
12	10, 11	eqeltrdi 2845	. . . . . 6 ⊢ (𝐴 = ∅ → 𝐴 ∈ Fin)
13	12	con3i 154	. . . . 5 ⊢ (¬ 𝐴 ∈ Fin → ¬ 𝐴 = ∅)
14	13	adantl 481	. . . 4 ⊢ ((𝐴 ∈ 𝑉 ∧ ¬ 𝐴 ∈ Fin) → ¬ 𝐴 = ∅)
15	9, 14	2falsed 376	. . 3 ⊢ ((𝐴 ∈ 𝑉 ∧ ¬ 𝐴 ∈ Fin) → ((♯‘𝐴) = 0 ↔ 𝐴 = ∅))
16	15	ex 412	. 2 ⊢ (𝐴 ∈ 𝑉 → (¬ 𝐴 ∈ Fin → ((♯‘𝐴) = 0 ↔ 𝐴 = ∅)))
17		hashen 14274	. . . 4 ⊢ ((𝐴 ∈ Fin ∧ ∅ ∈ Fin) → ((♯‘𝐴) = (♯‘∅) ↔ 𝐴 ≈ ∅))
18	11, 17	mpan2 692	. . 3 ⊢ (𝐴 ∈ Fin → ((♯‘𝐴) = (♯‘∅) ↔ 𝐴 ≈ ∅))
19		fz10 13465	. . . . . 6 ⊢ (1...0) = ∅
20	19	fveq2i 6838	. . . . 5 ⊢ (♯‘(1...0)) = (♯‘∅)
21		0nn0 12420	. . . . . 6 ⊢ 0 ∈ ℕ₀
22		hashfz1 14273	. . . . . 6 ⊢ (0 ∈ ℕ₀ → (♯‘(1...0)) = 0)
23	21, 22	ax-mp 5	. . . . 5 ⊢ (♯‘(1...0)) = 0
24	20, 23	eqtr3i 2762	. . . 4 ⊢ (♯‘∅) = 0
25	24	eqeq2i 2750	. . 3 ⊢ ((♯‘𝐴) = (♯‘∅) ↔ (♯‘𝐴) = 0)
26		en0 8959	. . 3 ⊢ (𝐴 ≈ ∅ ↔ 𝐴 = ∅)
27	18, 25, 26	3bitr3g 313	. 2 ⊢ (𝐴 ∈ Fin → ((♯‘𝐴) = 0 ↔ 𝐴 = ∅))
28	16, 27	pm2.61d2 181	1 ⊢ (𝐴 ∈ 𝑉 → ((♯‘𝐴) = 0 ↔ 𝐴 = ∅))

Colors of variables: wff setvar class

Syntax hints: ¬ wn 3 → wi 4 ↔ wb 206 ∧ wa 395 = wceq 1542 ∈ wcel 2114 ∅c0 4286 class class class wbr 5099 ‘cfv 6493 (class class class)co 7360 ≈ cen 8884 Fincfn 8887 ℝcr 11029 0cc0 11030 1c1 11031 +∞cpnf 11167 ℕ₀cn0 12405 ...cfz 13427 ♯chash 14257

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 1912 ax-6 1969 ax-7 2010 ax-8 2116 ax-9 2124 ax-10 2147 ax-11 2163 ax-12 2185 ax-ext 2709 ax-sep 5242 ax-nul 5252 ax-pow 5311 ax-pr 5378 ax-un 7682 ax-cnex 11086 ax-resscn 11087 ax-1cn 11088 ax-icn 11089 ax-addcl 11090 ax-addrcl 11091 ax-mulcl 11092 ax-mulrcl 11093 ax-mulcom 11094 ax-addass 11095 ax-mulass 11096 ax-distr 11097 ax-i2m1 11098 ax-1ne0 11099 ax-1rid 11100 ax-rnegex 11101 ax-rrecex 11102 ax-cnre 11103 ax-pre-lttri 11104 ax-pre-lttrn 11105 ax-pre-ltadd 11106 ax-pre-mulgt0 11107

This theorem depends on definitions: df-bi 207 df-an 396 df-or 849 df-3or 1088 df-3an 1089 df-tru 1545 df-fal 1555 df-ex 1782 df-nf 1786 df-sb 2069 df-mo 2540 df-eu 2570 df-clab 2716 df-cleq 2729 df-clel 2812 df-nfc 2886 df-ne 2934 df-nel 3038 df-ral 3053 df-rex 3062 df-reu 3352 df-rab 3401 df-v 3443 df-sbc 3742 df-csb 3851 df-dif 3905 df-un 3907 df-in 3909 df-ss 3919 df-pss 3922 df-nul 4287 df-if 4481 df-pw 4557 df-sn 4582 df-pr 4584 df-op 4588 df-uni 4865 df-int 4904 df-iun 4949 df-br 5100 df-opab 5162 df-mpt 5181 df-tr 5207 df-id 5520 df-eprel 5525 df-po 5533 df-so 5534 df-fr 5578 df-we 5580 df-xp 5631 df-rel 5632 df-cnv 5633 df-co 5634 df-dm 5635 df-rn 5636 df-res 5637 df-ima 5638 df-pred 6260 df-ord 6321 df-on 6322 df-lim 6323 df-suc 6324 df-iota 6449 df-fun 6495 df-fn 6496 df-f 6497 df-f1 6498 df-fo 6499 df-f1o 6500 df-fv 6501 df-riota 7317 df-ov 7363 df-oprab 7364 df-mpo 7365 df-om 7811 df-1st 7935 df-2nd 7936 df-frecs 8225 df-wrecs 8256 df-recs 8305 df-rdg 8343 df-1o 8399 df-er 8637 df-en 8888 df-dom 8889 df-sdom 8890 df-fin 8891 df-card 9855 df-pnf 11172 df-mnf 11173 df-xr 11174 df-ltxr 11175 df-le 11176 df-sub 11370 df-neg 11371 df-nn 12150 df-n0 12406 df-z 12493 df-uz 12756 df-fz 13428 df-hash 14258

This theorem is referenced by: hashneq0 14291 hashnncl 14293 hash0 14294 hashelne0d 14295 hashgt0 14315 hashle00 14327 seqcoll2 14392 prprrab 14400 hashle2pr 14404 hashge2el2difr 14408 ccat0 14503 ccat1st1st 14556 wrdind 14649 wrd2ind 14650 swrdccat3blem 14666 rev0 14691 repsw0 14704 cshwidx0 14733 fz1f1o 15637 hashbc0 16937 0hashbc 16939 ram0 16954 cshws0 17033 chnind 18548 chnub 18549 symgvalstruct 19330 gsmsymgrfix 19361 sylow1lem1 19531 sylow1lem4 19534 sylow2blem3 19555 frgpnabllem1 19806 0ringnnzr 20462 01eq0ringOLD 20468 vieta1lem2 26279 tgldimor 28557 uhgr0vsize0 29295 uhgr0edgfi 29296 usgr1v0e 29382 fusgrfisbase 29384 vtxd0nedgb 29545 vtxdusgr0edgnelALT 29553 usgrvd0nedg 29590 vtxdginducedm1lem4 29599 finsumvtxdg2size 29607 cyclnspth 29857 iswwlksnx 29896 umgrclwwlkge2 30049 clwwisshclwws 30073 hashecclwwlkn1 30135 umgrhashecclwwlk 30136 vdn0conngrumgrv2 30254 frgrwopreg 30381 frrusgrord0lem 30397 wlkl0 30425 frgrregord013 30453 frgrregord13 30454 frgrogt3nreg 30455 friendshipgt3 30456 hashne0 32871 wrdt2ind 33016 tocyc01 33181 esplyfval0 33703 vieta 33717 lvecdim0i 33743 hasheuni 34223 signstfvn 34707 signstfveq0a 34714 signshnz 34729 spthcycl 35304 usgrgt2cycl 35305 acycgr1v 35324 umgracycusgr 35329 cusgracyclt3v 35331 elmrsubrn 35695 fsuppind 42869 lindsrng01 48750

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