Theorem fo1st 8019

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 5393	. . . . 5 ⊢ {𝑥} ∈ V
2	1	dmex 7919	. . . 4 ⊢ dom {𝑥} ∈ V
3	2	uniex 7756	. . 3 ⊢ ∪ dom {𝑥} ∈ V
4		df-1st 7999	. . 3 ⊢ 1st = (𝑥 ∈ V ↦ ∪ dom {𝑥})
5	3, 4	fnmpti 6680	. 2 ⊢ 1st Fn V
6	4	rnmpt 5939	. . 3 ⊢ ran 1st = {𝑦 ∣ ∃𝑥 ∈ V 𝑦 = ∪ dom {𝑥}}
7		vex 3455	. . . . 5 ⊢ 𝑦 ∈ V
8		opex 5432	. . . . . 6 ⊢ ⟨𝑦, 𝑦⟩ ∈ V
9	7, 7	op1sta 6225	. . . . . . 7 ⊢ ∪ dom {⟨𝑦, 𝑦⟩} = 𝑦
10	9	eqcomi 2770	. . . . . 6 ⊢ 𝑦 = ∪ dom {⟨𝑦, 𝑦⟩}
11		sneq 4594	. . . . . . . . 9 ⊢ (𝑥 = ⟨𝑦, 𝑦⟩ → {𝑥} = {⟨𝑦, 𝑦⟩})
12	11	dmeqd 5887	. . . . . . . 8 ⊢ (𝑥 = ⟨𝑦, 𝑦⟩ → dom {𝑥} = dom {⟨𝑦, 𝑦⟩})
13	12	unieqd 4880	. . . . . . 7 ⊢ (𝑥 = ⟨𝑦, 𝑦⟩ → ∪ dom {𝑥} = ∪ dom {⟨𝑦, 𝑦⟩})
14	13	rspceeqv 3599	. . . . . 6 ⊢ ((⟨𝑦, 𝑦⟩ ∈ V ∧ 𝑦 = ∪ dom {⟨𝑦, 𝑦⟩}) → ∃𝑥 ∈ V 𝑦 = ∪ dom {𝑥})
15	8, 10, 14	mp2an 705	. . . . 5 ⊢ ∃𝑥 ∈ V 𝑦 = ∪ dom {𝑥}
16	7, 15	2th 267	. . . 4 ⊢ (𝑦 ∈ V ↔ ∃𝑥 ∈ V 𝑦 = ∪ dom {𝑥})
17	16	eqabi 2896	. . 3 ⊢ V = {𝑦 ∣ ∃𝑥 ∈ V 𝑦 = ∪ dom {𝑥}}
18	6, 17	eqtr4i 2787	. 2 ⊢ ran 1st = V
19		df-fo 6543	. 2 ⊢ (1st :V–onto→V ↔ (1st Fn V ∧ ran 1st = V))
20	5, 18, 19	mpbir2an 724	1 ⊢ 1st :V–onto→V

This proof depends on syntax axioms:   = wceq 1570   ∈ wcel 2145  {cab 2739  ∃wrex 3087  Vcvv 3451  {csn 4584  ⟨cop 4590  ∪ cuni 4867  dom cdm 5651  ran crn 5652   Fn wfn 6532  –onto→wfo 6535  1^st c1st 7997

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-8 2147  ax-9 2155  ax-10 2178  ax-11 2194  ax-12 2213  ax-ext 2733  ax-sep 5249  ax-pr 5391  ax-un 7749

This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-3an 1105  df-tru 1573  df-fal 1583  df-ex 1813  df-nf 1817  df-sb 2100  df-mo 2565  df-eu 2595  df-clab 2740  df-cleq 2753  df-clel 2836  df-nfc 2910  df-ral 3078  df-rex 3088  df-rab 3414  df-v 3453  df-dif 3902  df-un 3904  df-in 3906  df-ss 3916  df-nul 4280  df-if 4483  df-sn 4585  df-pr 4587  df-op 4591  df-uni 4868  df-br 5104  df-opab 5168  df-mpt 5187  df-id 5546  df-xp 5657  df-rel 5658  df-cnv 5659  df-co 5660  df-dm 5661  df-rn 5662  df-fun 6539  df-fn 6540  df-fo 6543  df-1st 7999

This theorem is used by:  br1steqg  8021  1stcof  8029  df1st2  8107  1stconst  8109  fsplit  8126  opco1  8132  fpwwe  10724  axpre-sup  11247  homadm  18208  homacd  18209  dmaf  18217  cdaf  18218  1stf1  18359  1stf2  18360  1stfcl  18364  upxp  23935  uptx  23937  cnmpt1st  23980  bcthlem4  25641  uniiccdif  25892  precsexlem10  28595  precsexlem11  28596  vafval  31198  smfval  31200  0vfval  31201  vsfval  31228  xppreima  33232  xppreima2  33238  1stpreimas  33292  1stpreima  33293  fsuppcurry2  33310  gsummpt2d  33603  cnre2csqima  34536  poimirlem26  38544  poimirlem27  38545