Theorem fo1st 7946

Description: The 1^st function maps the universe onto the universe. (Contributed by NM, 14-Oct-2004.) (Revised by Mario Carneiro, 8-Sep-2013.)

Assertion

Ref	Expression
fo1st	⊢ 1st :V–onto→V

Proof of Theorem fo1st

Dummy variables 𝑥 𝑦 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		vsnex 5391	. . . . 5 ⊢ {𝑥} ∈ V
2	1	dmex 7853	. . . 4 ⊢ dom {𝑥} ∈ V
3	2	uniex 7683	. . 3 ⊢ ∪ dom {𝑥} ∈ V
4		df-1st 7926	. . 3 ⊢ 1st = (𝑥 ∈ V ↦ ∪ dom {𝑥})
5	3, 4	fnmpti 6649	. 2 ⊢ 1st Fn V
6	4	rnmpt 5915	. . 3 ⊢ ran 1st = {𝑦 ∣ ∃𝑥 ∈ V 𝑦 = ∪ dom {𝑥}}
7		vex 3450	. . . . 5 ⊢ 𝑦 ∈ V
8		opex 5426	. . . . . 6 ⊢ ⟨𝑦, 𝑦⟩ ∈ V
9	7, 7	op1sta 6182	. . . . . . 7 ⊢ ∪ dom {⟨𝑦, 𝑦⟩} = 𝑦
10	9	eqcomi 2740	. . . . . 6 ⊢ 𝑦 = ∪ dom {⟨𝑦, 𝑦⟩}
11		sneq 4601	. . . . . . . . 9 ⊢ (𝑥 = ⟨𝑦, 𝑦⟩ → {𝑥} = {⟨𝑦, 𝑦⟩})
12	11	dmeqd 5866	. . . . . . . 8 ⊢ (𝑥 = ⟨𝑦, 𝑦⟩ → dom {𝑥} = dom {⟨𝑦, 𝑦⟩})
13	12	unieqd 4884	. . . . . . 7 ⊢ (𝑥 = ⟨𝑦, 𝑦⟩ → ∪ dom {𝑥} = ∪ dom {⟨𝑦, 𝑦⟩})
14	13	rspceeqv 3598	. . . . . 6 ⊢ ((⟨𝑦, 𝑦⟩ ∈ V ∧ 𝑦 = ∪ dom {⟨𝑦, 𝑦⟩}) → ∃𝑥 ∈ V 𝑦 = ∪ dom {𝑥})
15	8, 10, 14	mp2an 690	. . . . 5 ⊢ ∃𝑥 ∈ V 𝑦 = ∪ dom {𝑥}
16	7, 15	2th 263	. . . 4 ⊢ (𝑦 ∈ V ↔ ∃𝑥 ∈ V 𝑦 = ∪ dom {𝑥})
17	16	eqabi 2868	. . 3 ⊢ V = {𝑦 ∣ ∃𝑥 ∈ V 𝑦 = ∪ dom {𝑥}}
18	6, 17	eqtr4i 2762	. 2 ⊢ ran 1st = V
19		df-fo 6507	. 2 ⊢ (1st :V–onto→V ↔ (1st Fn V ∧ ran 1st = V))
20	5, 18, 19	mpbir2an 709	1 ⊢ 1st :V–onto→V

Syntax hints:   = wceq 1541   ∈ wcel 2106  {cab 2708  ∃wrex 3069  Vcvv 3446  {csn 4591  ⟨cop 4597  ∪ cuni 4870  dom cdm 5638  ran crn 5639   Fn wfn 6496  –onto→wfo 6499  1^st c1st 7924

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 2702  ax-sep 5261  ax-nul 5268  ax-pr 5389  ax-un 7677

This theorem depends on definitions:  df-bi 206  df-an 397  df-or 846  df-3an 1089  df-tru 1544  df-fal 1554  df-ex 1782  df-nf 1786  df-sb 2068  df-mo 2533  df-eu 2562  df-clab 2709  df-cleq 2723  df-clel 2809  df-nfc 2884  df-ral 3061  df-rex 3070  df-rab 3406  df-v 3448  df-dif 3916  df-un 3918  df-in 3920  df-ss 3930  df-nul 4288  df-if 4492  df-sn 4592  df-pr 4594  df-op 4598  df-uni 4871  df-br 5111  df-opab 5173  df-mpt 5194  df-id 5536  df-xp 5644  df-rel 5645  df-cnv 5646  df-co 5647  df-dm 5648  df-rn 5649  df-fun 6503  df-fn 6504  df-fo 6507  df-1st 7926

This theorem is referenced by:  br1steqg  7948  1stcof  7956  df1st2  8035  1stconst  8037  fsplit  8054  opco1  8060  fpwwe  10591  axpre-sup  11114  homadm  17940  homacd  17941  dmaf  17949  cdaf  17950  1stf1  18094  1stf2  18095  1stfcl  18099  upxp  23011  uptx  23013  cnmpt1st  23056  bcthlem4  24728  uniiccdif  24979  vafval  29608  smfval  29610  0vfval  29611  vsfval  29638  xppreima  31629  xppreima2  31634  1stpreimas  31687  1stpreima  31688  fsuppcurry2  31711  gsummpt2d  31961  cnre2csqima  32581  poimirlem26  36177  poimirlem27  36178