MPE Home Metamath Proof Explorer < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  MPE Home  >  Th. List  >  uniintsn Structured version   Visualization version   GIF version

Theorem uniintsn 4992
Description: Two ways to express "𝐴 is a singleton". See also en1 9021, en1b 9023, card1 9963, and eusn 4735. (Contributed by NM, 2-Aug-2010.)
Assertion
Ref Expression
uniintsn ( 𝐴 = 𝐴 ↔ ∃𝑥 𝐴 = {𝑥})
Distinct variable group:   𝑥,𝐴

Proof of Theorem uniintsn
Dummy variable 𝑦 is distinct from all other variables.
StepHypRef Expression
1 vn0 4339 . . . . . 6 V ≠ ∅
2 inteq 4954 . . . . . . . . . . 11 (𝐴 = ∅ → 𝐴 = ∅)
3 int0 4967 . . . . . . . . . . 11 ∅ = V
42, 3eqtrdi 2789 . . . . . . . . . 10 (𝐴 = ∅ → 𝐴 = V)
54adantl 483 . . . . . . . . 9 (( 𝐴 = 𝐴𝐴 = ∅) → 𝐴 = V)
6 unieq 4920 . . . . . . . . . . . 12 (𝐴 = ∅ → 𝐴 = ∅)
7 uni0 4940 . . . . . . . . . . . 12 ∅ = ∅
86, 7eqtrdi 2789 . . . . . . . . . . 11 (𝐴 = ∅ → 𝐴 = ∅)
9 eqeq1 2737 . . . . . . . . . . 11 ( 𝐴 = 𝐴 → ( 𝐴 = ∅ ↔ 𝐴 = ∅))
108, 9imbitrid 243 . . . . . . . . . 10 ( 𝐴 = 𝐴 → (𝐴 = ∅ → 𝐴 = ∅))
1110imp 408 . . . . . . . . 9 (( 𝐴 = 𝐴𝐴 = ∅) → 𝐴 = ∅)
125, 11eqtr3d 2775 . . . . . . . 8 (( 𝐴 = 𝐴𝐴 = ∅) → V = ∅)
1312ex 414 . . . . . . 7 ( 𝐴 = 𝐴 → (𝐴 = ∅ → V = ∅))
1413necon3d 2962 . . . . . 6 ( 𝐴 = 𝐴 → (V ≠ ∅ → 𝐴 ≠ ∅))
151, 14mpi 20 . . . . 5 ( 𝐴 = 𝐴𝐴 ≠ ∅)
16 n0 4347 . . . . 5 (𝐴 ≠ ∅ ↔ ∃𝑥 𝑥𝐴)
1715, 16sylib 217 . . . 4 ( 𝐴 = 𝐴 → ∃𝑥 𝑥𝐴)
18 vex 3479 . . . . . . 7 𝑥 ∈ V
19 vex 3479 . . . . . . 7 𝑦 ∈ V
2018, 19prss 4824 . . . . . 6 ((𝑥𝐴𝑦𝐴) ↔ {𝑥, 𝑦} ⊆ 𝐴)
21 uniss 4917 . . . . . . . . . . . 12 ({𝑥, 𝑦} ⊆ 𝐴 {𝑥, 𝑦} ⊆ 𝐴)
2221adantl 483 . . . . . . . . . . 11 (( 𝐴 = 𝐴 ∧ {𝑥, 𝑦} ⊆ 𝐴) → {𝑥, 𝑦} ⊆ 𝐴)
23 simpl 484 . . . . . . . . . . 11 (( 𝐴 = 𝐴 ∧ {𝑥, 𝑦} ⊆ 𝐴) → 𝐴 = 𝐴)
2422, 23sseqtrd 4023 . . . . . . . . . 10 (( 𝐴 = 𝐴 ∧ {𝑥, 𝑦} ⊆ 𝐴) → {𝑥, 𝑦} ⊆ 𝐴)
25 intss 4974 . . . . . . . . . . 11 ({𝑥, 𝑦} ⊆ 𝐴 𝐴 {𝑥, 𝑦})
2625adantl 483 . . . . . . . . . 10 (( 𝐴 = 𝐴 ∧ {𝑥, 𝑦} ⊆ 𝐴) → 𝐴 {𝑥, 𝑦})
2724, 26sstrd 3993 . . . . . . . . 9 (( 𝐴 = 𝐴 ∧ {𝑥, 𝑦} ⊆ 𝐴) → {𝑥, 𝑦} ⊆ {𝑥, 𝑦})
2818, 19unipr 4927 . . . . . . . . 9 {𝑥, 𝑦} = (𝑥𝑦)
2918, 19intpr 4987 . . . . . . . . 9 {𝑥, 𝑦} = (𝑥𝑦)
3027, 28, 293sstr3g 4027 . . . . . . . 8 (( 𝐴 = 𝐴 ∧ {𝑥, 𝑦} ⊆ 𝐴) → (𝑥𝑦) ⊆ (𝑥𝑦))
31 inss1 4229 . . . . . . . . 9 (𝑥𝑦) ⊆ 𝑥
32 ssun1 4173 . . . . . . . . 9 𝑥 ⊆ (𝑥𝑦)
3331, 32sstri 3992 . . . . . . . 8 (𝑥𝑦) ⊆ (𝑥𝑦)
34 eqss 3998 . . . . . . . . 9 ((𝑥𝑦) = (𝑥𝑦) ↔ ((𝑥𝑦) ⊆ (𝑥𝑦) ∧ (𝑥𝑦) ⊆ (𝑥𝑦)))
35 uneqin 4279 . . . . . . . . 9 ((𝑥𝑦) = (𝑥𝑦) ↔ 𝑥 = 𝑦)
3634, 35bitr3i 277 . . . . . . . 8 (((𝑥𝑦) ⊆ (𝑥𝑦) ∧ (𝑥𝑦) ⊆ (𝑥𝑦)) ↔ 𝑥 = 𝑦)
3730, 33, 36sylanblc 590 . . . . . . 7 (( 𝐴 = 𝐴 ∧ {𝑥, 𝑦} ⊆ 𝐴) → 𝑥 = 𝑦)
3837ex 414 . . . . . 6 ( 𝐴 = 𝐴 → ({𝑥, 𝑦} ⊆ 𝐴𝑥 = 𝑦))
3920, 38biimtrid 241 . . . . 5 ( 𝐴 = 𝐴 → ((𝑥𝐴𝑦𝐴) → 𝑥 = 𝑦))
4039alrimivv 1932 . . . 4 ( 𝐴 = 𝐴 → ∀𝑥𝑦((𝑥𝐴𝑦𝐴) → 𝑥 = 𝑦))
4117, 40jca 513 . . 3 ( 𝐴 = 𝐴 → (∃𝑥 𝑥𝐴 ∧ ∀𝑥𝑦((𝑥𝐴𝑦𝐴) → 𝑥 = 𝑦)))
42 euabsn 4731 . . . 4 (∃!𝑥 𝑥𝐴 ↔ ∃𝑥{𝑥𝑥𝐴} = {𝑥})
43 eleq1w 2817 . . . . 5 (𝑥 = 𝑦 → (𝑥𝐴𝑦𝐴))
4443eu4 2612 . . . 4 (∃!𝑥 𝑥𝐴 ↔ (∃𝑥 𝑥𝐴 ∧ ∀𝑥𝑦((𝑥𝐴𝑦𝐴) → 𝑥 = 𝑦)))
45 abid2 2872 . . . . . 6 {𝑥𝑥𝐴} = 𝐴
4645eqeq1i 2738 . . . . 5 ({𝑥𝑥𝐴} = {𝑥} ↔ 𝐴 = {𝑥})
4746exbii 1851 . . . 4 (∃𝑥{𝑥𝑥𝐴} = {𝑥} ↔ ∃𝑥 𝐴 = {𝑥})
4842, 44, 473bitr3i 301 . . 3 ((∃𝑥 𝑥𝐴 ∧ ∀𝑥𝑦((𝑥𝐴𝑦𝐴) → 𝑥 = 𝑦)) ↔ ∃𝑥 𝐴 = {𝑥})
4941, 48sylib 217 . 2 ( 𝐴 = 𝐴 → ∃𝑥 𝐴 = {𝑥})
50 unisnv 4932 . . . 4 {𝑥} = 𝑥
51 unieq 4920 . . . 4 (𝐴 = {𝑥} → 𝐴 = {𝑥})
52 inteq 4954 . . . . 5 (𝐴 = {𝑥} → 𝐴 = {𝑥})
5318intsn 4991 . . . . 5 {𝑥} = 𝑥
5452, 53eqtrdi 2789 . . . 4 (𝐴 = {𝑥} → 𝐴 = 𝑥)
5550, 51, 543eqtr4a 2799 . . 3 (𝐴 = {𝑥} → 𝐴 = 𝐴)
5655exlimiv 1934 . 2 (∃𝑥 𝐴 = {𝑥} → 𝐴 = 𝐴)
5749, 56impbii 208 1 ( 𝐴 = 𝐴 ↔ ∃𝑥 𝐴 = {𝑥})
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 205  wa 397  wal 1540   = wceq 1542  wex 1782  wcel 2107  ∃!weu 2563  {cab 2710  wne 2941  Vcvv 3475  cun 3947  cin 3948  wss 3949  c0 4323  {csn 4629  {cpr 4631   cuni 4909   cint 4951
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1798  ax-4 1812  ax-5 1914  ax-6 1972  ax-7 2012  ax-8 2109  ax-9 2117  ax-10 2138  ax-11 2155  ax-12 2172  ax-ext 2704
This theorem depends on definitions:  df-bi 206  df-an 398  df-or 847  df-tru 1545  df-fal 1555  df-ex 1783  df-nf 1787  df-sb 2069  df-mo 2535  df-eu 2564  df-clab 2711  df-cleq 2725  df-clel 2811  df-nfc 2886  df-ne 2942  df-ral 3063  df-rex 3072  df-rab 3434  df-v 3477  df-dif 3952  df-un 3954  df-in 3956  df-ss 3966  df-nul 4324  df-sn 4630  df-pr 4632  df-uni 4910  df-int 4952
This theorem is referenced by:  uniintab  4993
  Copyright terms: Public domain W3C validator