Theorem fifo 9470

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 4795	. . . . . 6 ⊢ (𝑦 ∈ ((𝒫 𝐴 ∩ Fin) ∖ {∅}) → 𝑦 ≠ ∅)
2		intex 5350	. . . . . 6 ⊢ (𝑦 ≠ ∅ ↔ ∩ 𝑦 ∈ V)
3	1, 2	sylib 218	. . . . 5 ⊢ (𝑦 ∈ ((𝒫 𝐴 ∩ Fin) ∖ {∅}) → ∩ 𝑦 ∈ V)
4	3	rgen 3061	. . . 4 ⊢ ∀𝑦 ∈ ((𝒫 𝐴 ∩ Fin) ∖ {∅})∩ 𝑦 ∈ V
5		fifo.1	. . . . 5 ⊢ 𝐹 = (𝑦 ∈ ((𝒫 𝐴 ∩ Fin) ∖ {∅}) ↦ ∩ 𝑦)
6	5	fnmpt 6709	. . . 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 6827	. . 3 ⊢ (𝐹 Fn ((𝒫 𝐴 ∩ Fin) ∖ {∅}) ↔ 𝐹:((𝒫 𝐴 ∩ Fin) ∖ {∅})–onto→ran 𝐹)
9	7, 8	sylib 218	. 2 ⊢ (𝐴 ∈ 𝑉 → 𝐹:((𝒫 𝐴 ∩ Fin) ∖ {∅})–onto→ran 𝐹)
10		elfi2 9452	. . . . 5 ⊢ (𝐴 ∈ 𝑉 → (𝑥 ∈ (fi‘𝐴) ↔ ∃𝑦 ∈ ((𝒫 𝐴 ∩ Fin) ∖ {∅})𝑥 = ∩ 𝑦))
11	5	elrnmpt 5972	. . . . . 6 ⊢ (𝑥 ∈ V → (𝑥 ∈ ran 𝐹 ↔ ∃𝑦 ∈ ((𝒫 𝐴 ∩ Fin) ∖ {∅})𝑥 = ∩ 𝑦))
12	11	elv 3483	. . . . 5 ⊢ (𝑥 ∈ ran 𝐹 ↔ ∃𝑦 ∈ ((𝒫 𝐴 ∩ Fin) ∖ {∅})𝑥 = ∩ 𝑦)
13	10, 12	bitr4di 289	. . . 4 ⊢ (𝐴 ∈ 𝑉 → (𝑥 ∈ (fi‘𝐴) ↔ 𝑥 ∈ ran 𝐹))
14	13	eqrdv 2733	. . 3 ⊢ (𝐴 ∈ 𝑉 → (fi‘𝐴) = ran 𝐹)
15		foeq3 6819	. . 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 257	1 ⊢ (𝐴 ∈ 𝑉 → 𝐹:((𝒫 𝐴 ∩ Fin) ∖ {∅})–onto→(fi‘𝐴))

Syntax hints:   → wi 4   ↔ wb 206   = wceq 1537   ∈ wcel 2106   ≠ wne 2938  ∀wral 3059  ∃wrex 3068  Vcvv 3478   ∖ cdif 3960   ∩ cin 3962  ∅c0 4339  𝒫 cpw 4605  {csn 4631  ∩ cint 4951   ↦ cmpt 5231  ran crn 5690   Fn wfn 6558  –onto→wfo 6561  ‘cfv 6563  Fincfn 8984  ficfi 9448

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1792  ax-4 1806  ax-5 1908  ax-6 1965  ax-7 2005  ax-8 2108  ax-9 2116  ax-10 2139  ax-11 2155  ax-12 2175  ax-ext 2706  ax-sep 5302  ax-nul 5312  ax-pow 5371  ax-pr 5438  ax-un 7754

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3an 1088  df-tru 1540  df-fal 1550  df-ex 1777  df-nf 1781  df-sb 2063  df-mo 2538  df-eu 2567  df-clab 2713  df-cleq 2727  df-clel 2814  df-nfc 2890  df-ne 2939  df-ral 3060  df-rex 3069  df-rab 3434  df-v 3480  df-dif 3966  df-un 3968  df-in 3970  df-ss 3980  df-nul 4340  df-if 4532  df-pw 4607  df-sn 4632  df-pr 4634  df-op 4638  df-uni 4913  df-int 4952  df-br 5149  df-opab 5211  df-mpt 5232  df-id 5583  df-xp 5695  df-rel 5696  df-cnv 5697  df-co 5698  df-dm 5699  df-rn 5700  df-iota 6516  df-fun 6565  df-fn 6566  df-fo 6569  df-fv 6571  df-fi 9449

This theorem is referenced by:  inffien  10101  fictb  10282