Theorem fifo 8880

Description: Describe a surjection from nonempty finite sets to finite intersections. (Contributed by Mario Carneiro, 18-May-2015.)

Hypothesis

Ref	Expression
fifo.1	⊢ 𝐹 = (𝑦 ∈ ((𝒫 𝐴 ∩ Fin) ∖ {∅}) ↦ ∩ 𝑦)

Assertion

Ref	Expression
fifo	⊢ (𝐴 ∈ 𝑉 → 𝐹:((𝒫 𝐴 ∩ Fin) ∖ {∅})–onto→(fi‘𝐴))

Distinct variable groups:   𝑦,𝐴   𝑦,𝑉

Allowed substitution hint:   𝐹(𝑦)

Proof of Theorem fifo

Dummy variable 𝑥 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		eldifsni 4683	. . . . . 6 ⊢ (𝑦 ∈ ((𝒫 𝐴 ∩ Fin) ∖ {∅}) → 𝑦 ≠ ∅)
2		intex 5204	. . . . . 6 ⊢ (𝑦 ≠ ∅ ↔ ∩ 𝑦 ∈ V)
3	1, 2	sylib 221	. . . . 5 ⊢ (𝑦 ∈ ((𝒫 𝐴 ∩ Fin) ∖ {∅}) → ∩ 𝑦 ∈ V)
4	3	rgen 3116	. . . 4 ⊢ ∀𝑦 ∈ ((𝒫 𝐴 ∩ Fin) ∖ {∅})∩ 𝑦 ∈ V
5		fifo.1	. . . . 5 ⊢ 𝐹 = (𝑦 ∈ ((𝒫 𝐴 ∩ Fin) ∖ {∅}) ↦ ∩ 𝑦)
6	5	fnmpt 6460	. . . 4 ⊢ (∀𝑦 ∈ ((𝒫 𝐴 ∩ Fin) ∖ {∅})∩ 𝑦 ∈ V → 𝐹 Fn ((𝒫 𝐴 ∩ Fin) ∖ {∅}))
7	4, 6	mp1i 13	. . 3 ⊢ (𝐴 ∈ 𝑉 → 𝐹 Fn ((𝒫 𝐴 ∩ Fin) ∖ {∅}))
8		dffn4 6571	. . 3 ⊢ (𝐹 Fn ((𝒫 𝐴 ∩ Fin) ∖ {∅}) ↔ 𝐹:((𝒫 𝐴 ∩ Fin) ∖ {∅})–onto→ran 𝐹)
9	7, 8	sylib 221	. 2 ⊢ (𝐴 ∈ 𝑉 → 𝐹:((𝒫 𝐴 ∩ Fin) ∖ {∅})–onto→ran 𝐹)
10		elfi2 8862	. . . . 5 ⊢ (𝐴 ∈ 𝑉 → (𝑥 ∈ (fi‘𝐴) ↔ ∃𝑦 ∈ ((𝒫 𝐴 ∩ Fin) ∖ {∅})𝑥 = ∩ 𝑦))
11	5	elrnmpt 5792	. . . . . 6 ⊢ (𝑥 ∈ V → (𝑥 ∈ ran 𝐹 ↔ ∃𝑦 ∈ ((𝒫 𝐴 ∩ Fin) ∖ {∅})𝑥 = ∩ 𝑦))
12	11	elv 3446	. . . . 5 ⊢ (𝑥 ∈ ran 𝐹 ↔ ∃𝑦 ∈ ((𝒫 𝐴 ∩ Fin) ∖ {∅})𝑥 = ∩ 𝑦)
13	10, 12	syl6bbr 292	. . . 4 ⊢ (𝐴 ∈ 𝑉 → (𝑥 ∈ (fi‘𝐴) ↔ 𝑥 ∈ ran 𝐹))
14	13	eqrdv 2796	. . 3 ⊢ (𝐴 ∈ 𝑉 → (fi‘𝐴) = ran 𝐹)
15		foeq3 6563	. . 3 ⊢ ((fi‘𝐴) = ran 𝐹 → (𝐹:((𝒫 𝐴 ∩ Fin) ∖ {∅})–onto→(fi‘𝐴) ↔ 𝐹:((𝒫 𝐴 ∩ Fin) ∖ {∅})–onto→ran 𝐹))
16	14, 15	syl 17	. 2 ⊢ (𝐴 ∈ 𝑉 → (𝐹:((𝒫 𝐴 ∩ Fin) ∖ {∅})–onto→(fi‘𝐴) ↔ 𝐹:((𝒫 𝐴 ∩ Fin) ∖ {∅})–onto→ran 𝐹))
17	9, 16	mpbird 260	1 ⊢ (𝐴 ∈ 𝑉 → 𝐹:((𝒫 𝐴 ∩ Fin) ∖ {∅})–onto→(fi‘𝐴))

Syntax hints:   → wi 4   ↔ wb 209   = wceq 1538   ∈ wcel 2111   ≠ wne 2987  ∀wral 3106  ∃wrex 3107  Vcvv 3441   ∖ cdif 3878   ∩ cin 3880  ∅c0 4243  𝒫 cpw 4497  {csn 4525  ∩ cint 4838   ↦ cmpt 5110  ran crn 5520   Fn wfn 6319  –onto→wfo 6322  ‘cfv 6324  Fincfn 8492  ficfi 8858

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 1911  ax-6 1970  ax-7 2015  ax-8 2113  ax-9 2121  ax-10 2142  ax-11 2158  ax-12 2175  ax-ext 2770  ax-sep 5167  ax-nul 5174  ax-pow 5231  ax-pr 5295  ax-un 7441

This theorem depends on definitions:  df-bi 210  df-an 400  df-or 845  df-3an 1086  df-tru 1541  df-ex 1782  df-nf 1786  df-sb 2070  df-mo 2598  df-eu 2629  df-clab 2777  df-cleq 2791  df-clel 2870  df-nfc 2938  df-ne 2988  df-ral 3111  df-rex 3112  df-rab 3115  df-v 3443  df-sbc 3721  df-dif 3884  df-un 3886  df-in 3888  df-ss 3898  df-nul 4244  df-if 4426  df-pw 4499  df-sn 4526  df-pr 4528  df-op 4532  df-uni 4801  df-int 4839  df-br 5031  df-opab 5093  df-mpt 5111  df-id 5425  df-xp 5525  df-rel 5526  df-cnv 5527  df-co 5528  df-dm 5529  df-rn 5530  df-iota 6283  df-fun 6326  df-fn 6327  df-fo 6330  df-fv 6332  df-fi 8859

This theorem is referenced by:  inffien  9474  fictb  9656