ILE Home Intuitionistic Logic Explorer < Previous   Next >
Nearby theorems
Mirrors  >  Home  >  ILE Home  >  Th. List  >  rabeq0 GIF version

Theorem rabeq0 3521
Description: Condition for a restricted class abstraction to be empty. (Contributed by Jeff Madsen, 7-Jun-2010.)
Assertion
Ref Expression
rabeq0 ({𝑥𝐴𝜑} = ∅ ↔ ∀𝑥𝐴 ¬ 𝜑)

Proof of Theorem rabeq0
Dummy variable 𝑦 is distinct from all other variables.
StepHypRef Expression
1 imnan 694 . . 3 ((𝑥𝐴 → ¬ 𝜑) ↔ ¬ (𝑥𝐴𝜑))
21albii 1516 . 2 (∀𝑥(𝑥𝐴 → ¬ 𝜑) ↔ ∀𝑥 ¬ (𝑥𝐴𝜑))
3 df-ral 2513 . 2 (∀𝑥𝐴 ¬ 𝜑 ↔ ∀𝑥(𝑥𝐴 → ¬ 𝜑))
4 sbn 2003 . . . 4 ([𝑦 / 𝑥] ¬ (𝑥𝐴𝜑) ↔ ¬ [𝑦 / 𝑥](𝑥𝐴𝜑))
54albii 1516 . . 3 (∀𝑦[𝑦 / 𝑥] ¬ (𝑥𝐴𝜑) ↔ ∀𝑦 ¬ [𝑦 / 𝑥](𝑥𝐴𝜑))
6 nfv 1574 . . . 4 𝑦 ¬ (𝑥𝐴𝜑)
76sb8 1902 . . 3 (∀𝑥 ¬ (𝑥𝐴𝜑) ↔ ∀𝑦[𝑦 / 𝑥] ¬ (𝑥𝐴𝜑))
8 eq0 3510 . . . 4 ({𝑥𝐴𝜑} = ∅ ↔ ∀𝑦 ¬ 𝑦 ∈ {𝑥𝐴𝜑})
9 df-rab 2517 . . . . . . . 8 {𝑥𝐴𝜑} = {𝑥 ∣ (𝑥𝐴𝜑)}
109eleq2i 2296 . . . . . . 7 (𝑦 ∈ {𝑥𝐴𝜑} ↔ 𝑦 ∈ {𝑥 ∣ (𝑥𝐴𝜑)})
11 df-clab 2216 . . . . . . 7 (𝑦 ∈ {𝑥 ∣ (𝑥𝐴𝜑)} ↔ [𝑦 / 𝑥](𝑥𝐴𝜑))
1210, 11bitri 184 . . . . . 6 (𝑦 ∈ {𝑥𝐴𝜑} ↔ [𝑦 / 𝑥](𝑥𝐴𝜑))
1312notbii 672 . . . . 5 𝑦 ∈ {𝑥𝐴𝜑} ↔ ¬ [𝑦 / 𝑥](𝑥𝐴𝜑))
1413albii 1516 . . . 4 (∀𝑦 ¬ 𝑦 ∈ {𝑥𝐴𝜑} ↔ ∀𝑦 ¬ [𝑦 / 𝑥](𝑥𝐴𝜑))
158, 14bitri 184 . . 3 ({𝑥𝐴𝜑} = ∅ ↔ ∀𝑦 ¬ [𝑦 / 𝑥](𝑥𝐴𝜑))
165, 7, 153bitr4ri 213 . 2 ({𝑥𝐴𝜑} = ∅ ↔ ∀𝑥 ¬ (𝑥𝐴𝜑))
172, 3, 163bitr4ri 213 1 ({𝑥𝐴𝜑} = ∅ ↔ ∀𝑥𝐴 ¬ 𝜑)
Colors of variables: wff set class
Syntax hints:  ¬ wn 3  wi 4  wa 104  wb 105  wal 1393   = wceq 1395  [wsb 1808  wcel 2200  {cab 2215  wral 2508  {crab 2512  c0 3491
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 617  ax-in2 618  ax-io 714  ax-5 1493  ax-7 1494  ax-gen 1495  ax-ie1 1539  ax-ie2 1540  ax-8 1550  ax-10 1551  ax-11 1552  ax-i12 1553  ax-bndl 1555  ax-4 1556  ax-17 1572  ax-i9 1576  ax-ial 1580  ax-i5r 1581  ax-ext 2211
This theorem depends on definitions:  df-bi 117  df-tru 1398  df-fal 1401  df-nf 1507  df-sb 1809  df-clab 2216  df-cleq 2222  df-clel 2225  df-nfc 2361  df-ral 2513  df-rab 2517  df-v 2801  df-dif 3199  df-nul 3492
This theorem is referenced by:  rabnc  3524  rabrsndc  3734  exmidsssnc  4286  ssfilem  7033  diffitest  7045  ssfirab  7094  ctssexmid  7313  exmidonfinlem  7367  iooidg  10101  icc0r  10118  fznlem  10233  ioo0  10474  ico0  10476  ioc0  10477  phiprmpw  12739  hashgcdeq  12757  unennn  12963  znnen  12964  fczpsrbag  14629  lgsquadlem2  15751  pw0ss  15877  umgrnloop0  15911  lfgrnloopen  15925
  Copyright terms: Public domain W3C validator