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Theorem fparlem1 8116
Description: Lemma for fpar 8120. (Contributed by NM, 22-Dec-2008.) (Revised by Mario Carneiro, 28-Apr-2015.)
Assertion
Ref Expression
fparlem1 ((1st ↾ (V × V)) “ {𝑥}) = ({𝑥} × V)

Proof of Theorem fparlem1
Dummy variable 𝑦 is distinct from all other variables.
StepHypRef Expression
1 fvres 6900 . . . . . 6 (𝑦 ∈ (V × V) → ((1st ↾ (V × V))‘𝑦) = (1st𝑦))
21eqeq1d 2738 . . . . 5 (𝑦 ∈ (V × V) → (((1st ↾ (V × V))‘𝑦) = 𝑥 ↔ (1st𝑦) = 𝑥))
3 vex 3468 . . . . . . 7 𝑥 ∈ V
43elsn2 4646 . . . . . 6 ((1st𝑦) ∈ {𝑥} ↔ (1st𝑦) = 𝑥)
5 fvex 6894 . . . . . . 7 (2nd𝑦) ∈ V
65biantru 529 . . . . . 6 ((1st𝑦) ∈ {𝑥} ↔ ((1st𝑦) ∈ {𝑥} ∧ (2nd𝑦) ∈ V))
74, 6bitr3i 277 . . . . 5 ((1st𝑦) = 𝑥 ↔ ((1st𝑦) ∈ {𝑥} ∧ (2nd𝑦) ∈ V))
82, 7bitrdi 287 . . . 4 (𝑦 ∈ (V × V) → (((1st ↾ (V × V))‘𝑦) = 𝑥 ↔ ((1st𝑦) ∈ {𝑥} ∧ (2nd𝑦) ∈ V)))
98pm5.32i 574 . . 3 ((𝑦 ∈ (V × V) ∧ ((1st ↾ (V × V))‘𝑦) = 𝑥) ↔ (𝑦 ∈ (V × V) ∧ ((1st𝑦) ∈ {𝑥} ∧ (2nd𝑦) ∈ V)))
10 f1stres 8017 . . . 4 (1st ↾ (V × V)):(V × V)⟶V
11 ffn 6711 . . . 4 ((1st ↾ (V × V)):(V × V)⟶V → (1st ↾ (V × V)) Fn (V × V))
12 fniniseg 7055 . . . 4 ((1st ↾ (V × V)) Fn (V × V) → (𝑦 ∈ ((1st ↾ (V × V)) “ {𝑥}) ↔ (𝑦 ∈ (V × V) ∧ ((1st ↾ (V × V))‘𝑦) = 𝑥)))
1310, 11, 12mp2b 10 . . 3 (𝑦 ∈ ((1st ↾ (V × V)) “ {𝑥}) ↔ (𝑦 ∈ (V × V) ∧ ((1st ↾ (V × V))‘𝑦) = 𝑥))
14 elxp7 8028 . . 3 (𝑦 ∈ ({𝑥} × V) ↔ (𝑦 ∈ (V × V) ∧ ((1st𝑦) ∈ {𝑥} ∧ (2nd𝑦) ∈ V)))
159, 13, 143bitr4i 303 . 2 (𝑦 ∈ ((1st ↾ (V × V)) “ {𝑥}) ↔ 𝑦 ∈ ({𝑥} × V))
1615eqriv 2733 1 ((1st ↾ (V × V)) “ {𝑥}) = ({𝑥} × V)
Colors of variables: wff setvar class
Syntax hints:  wb 206  wa 395   = wceq 1540  wcel 2109  Vcvv 3464  {csn 4606   × cxp 5657  ccnv 5658  cres 5661  cima 5662   Fn wfn 6531  wf 6532  cfv 6536  1st c1st 7991  2nd c2nd 7992
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1795  ax-4 1809  ax-5 1910  ax-6 1967  ax-7 2008  ax-8 2111  ax-9 2119  ax-10 2142  ax-11 2158  ax-12 2178  ax-ext 2708  ax-sep 5271  ax-nul 5281  ax-pr 5407  ax-un 7734
This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3an 1088  df-tru 1543  df-fal 1553  df-ex 1780  df-nf 1784  df-sb 2066  df-mo 2540  df-eu 2569  df-clab 2715  df-cleq 2728  df-clel 2810  df-nfc 2886  df-ne 2934  df-ral 3053  df-rex 3062  df-rab 3421  df-v 3466  df-sbc 3771  df-csb 3880  df-dif 3934  df-un 3936  df-in 3938  df-ss 3948  df-nul 4314  df-if 4506  df-sn 4607  df-pr 4609  df-op 4613  df-uni 4889  df-iun 4974  df-br 5125  df-opab 5187  df-mpt 5207  df-id 5553  df-xp 5665  df-rel 5666  df-cnv 5667  df-co 5668  df-dm 5669  df-rn 5670  df-res 5671  df-ima 5672  df-iota 6489  df-fun 6538  df-fn 6539  df-f 6540  df-fv 6544  df-1st 7993  df-2nd 7994
This theorem is referenced by:  fparlem3  8118
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