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Theorem inelfi 8870
 Description: The intersection of two sets is a finite intersection. (Contributed by Thierry Arnoux, 6-Jan-2017.)
Assertion
Ref Expression
inelfi ((𝑋𝑉𝐴𝑋𝐵𝑋) → (𝐴𝐵) ∈ (fi‘𝑋))

Proof of Theorem inelfi
Dummy variable 𝑝 is distinct from all other variables.
StepHypRef Expression
1 prelpwi 5308 . . . . 5 ((𝐴𝑋𝐵𝑋) → {𝐴, 𝐵} ∈ 𝒫 𝑋)
213adant1 1127 . . . 4 ((𝑋𝑉𝐴𝑋𝐵𝑋) → {𝐴, 𝐵} ∈ 𝒫 𝑋)
3 prfi 8781 . . . . 5 {𝐴, 𝐵} ∈ Fin
43a1i 11 . . . 4 ((𝑋𝑉𝐴𝑋𝐵𝑋) → {𝐴, 𝐵} ∈ Fin)
52, 4elind 4124 . . 3 ((𝑋𝑉𝐴𝑋𝐵𝑋) → {𝐴, 𝐵} ∈ (𝒫 𝑋 ∩ Fin))
6 intprg 4875 . . . . 5 ((𝐴𝑋𝐵𝑋) → {𝐴, 𝐵} = (𝐴𝐵))
763adant1 1127 . . . 4 ((𝑋𝑉𝐴𝑋𝐵𝑋) → {𝐴, 𝐵} = (𝐴𝐵))
87eqcomd 2807 . . 3 ((𝑋𝑉𝐴𝑋𝐵𝑋) → (𝐴𝐵) = {𝐴, 𝐵})
9 inteq 4844 . . . 4 (𝑝 = {𝐴, 𝐵} → 𝑝 = {𝐴, 𝐵})
109rspceeqv 3589 . . 3 (({𝐴, 𝐵} ∈ (𝒫 𝑋 ∩ Fin) ∧ (𝐴𝐵) = {𝐴, 𝐵}) → ∃𝑝 ∈ (𝒫 𝑋 ∩ Fin)(𝐴𝐵) = 𝑝)
115, 8, 10syl2anc 587 . 2 ((𝑋𝑉𝐴𝑋𝐵𝑋) → ∃𝑝 ∈ (𝒫 𝑋 ∩ Fin)(𝐴𝐵) = 𝑝)
12 inex1g 5190 . . . 4 (𝐴𝑋 → (𝐴𝐵) ∈ V)
13123ad2ant2 1131 . . 3 ((𝑋𝑉𝐴𝑋𝐵𝑋) → (𝐴𝐵) ∈ V)
14 simp1 1133 . . 3 ((𝑋𝑉𝐴𝑋𝐵𝑋) → 𝑋𝑉)
15 elfi 8865 . . 3 (((𝐴𝐵) ∈ V ∧ 𝑋𝑉) → ((𝐴𝐵) ∈ (fi‘𝑋) ↔ ∃𝑝 ∈ (𝒫 𝑋 ∩ Fin)(𝐴𝐵) = 𝑝))
1613, 14, 15syl2anc 587 . 2 ((𝑋𝑉𝐴𝑋𝐵𝑋) → ((𝐴𝐵) ∈ (fi‘𝑋) ↔ ∃𝑝 ∈ (𝒫 𝑋 ∩ Fin)(𝐴𝐵) = 𝑝))
1711, 16mpbird 260 1 ((𝑋𝑉𝐴𝑋𝐵𝑋) → (𝐴𝐵) ∈ (fi‘𝑋))
 Colors of variables: wff setvar class Syntax hints:   → wi 4   ↔ wb 209   ∧ w3a 1084   = wceq 1538   ∈ wcel 2112  ∃wrex 3110  Vcvv 3444   ∩ cin 3883  𝒫 cpw 4500  {cpr 4530  ∩ cint 4841  ‘cfv 6328  Fincfn 8496  ficfi 8862 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 2114  ax-9 2122  ax-10 2143  ax-11 2159  ax-12 2176  ax-ext 2773  ax-sep 5170  ax-nul 5177  ax-pow 5234  ax-pr 5298  ax-un 7445 This theorem depends on definitions:  df-bi 210  df-an 400  df-or 845  df-3or 1085  df-3an 1086  df-tru 1541  df-ex 1782  df-nf 1786  df-sb 2070  df-mo 2601  df-eu 2632  df-clab 2780  df-cleq 2794  df-clel 2873  df-nfc 2941  df-ne 2991  df-ral 3114  df-rex 3115  df-reu 3116  df-rab 3118  df-v 3446  df-sbc 3724  df-csb 3832  df-dif 3887  df-un 3889  df-in 3891  df-ss 3901  df-pss 3903  df-nul 4247  df-if 4429  df-pw 4502  df-sn 4529  df-pr 4531  df-tp 4533  df-op 4535  df-uni 4804  df-int 4842  df-iun 4886  df-br 5034  df-opab 5096  df-mpt 5114  df-tr 5140  df-id 5428  df-eprel 5433  df-po 5442  df-so 5443  df-fr 5482  df-we 5484  df-xp 5529  df-rel 5530  df-cnv 5531  df-co 5532  df-dm 5533  df-rn 5534  df-res 5535  df-ima 5536  df-pred 6120  df-ord 6166  df-on 6167  df-lim 6168  df-suc 6169  df-iota 6287  df-fun 6330  df-fn 6331  df-f 6332  df-f1 6333  df-fo 6334  df-f1o 6335  df-fv 6336  df-ov 7142  df-oprab 7143  df-mpo 7144  df-om 7565  df-wrecs 7934  df-recs 7995  df-rdg 8033  df-1o 8089  df-oadd 8093  df-er 8276  df-en 8497  df-fin 8500  df-fi 8863 This theorem is referenced by:  neiptoptop  21739  sigapildsyslem  31528
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