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Theorem reapti 8623
Description: Real apartness is tight. Beyond the development of apartness itself, proofs should use apti 8666. (Contributed by Jim Kingdon, 30-Jan-2020.) (New usage is discouraged.)
Assertion
Ref Expression
reapti ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (𝐴 = 𝐵 ↔ ¬ 𝐴 # 𝐵))

Proof of Theorem reapti
StepHypRef Expression
1 ltnr 8120 . . . . 5 (𝐴 ∈ ℝ → ¬ 𝐴 < 𝐴)
21adantr 276 . . . 4 ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → ¬ 𝐴 < 𝐴)
3 oridm 758 . . . . . 6 ((𝐴 < 𝐴𝐴 < 𝐴) ↔ 𝐴 < 𝐴)
4 breq2 4038 . . . . . . 7 (𝐴 = 𝐵 → (𝐴 < 𝐴𝐴 < 𝐵))
5 breq1 4037 . . . . . . 7 (𝐴 = 𝐵 → (𝐴 < 𝐴𝐵 < 𝐴))
64, 5orbi12d 794 . . . . . 6 (𝐴 = 𝐵 → ((𝐴 < 𝐴𝐴 < 𝐴) ↔ (𝐴 < 𝐵𝐵 < 𝐴)))
73, 6bitr3id 194 . . . . 5 (𝐴 = 𝐵 → (𝐴 < 𝐴 ↔ (𝐴 < 𝐵𝐵 < 𝐴)))
87notbid 668 . . . 4 (𝐴 = 𝐵 → (¬ 𝐴 < 𝐴 ↔ ¬ (𝐴 < 𝐵𝐵 < 𝐴)))
92, 8syl5ibcom 155 . . 3 ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (𝐴 = 𝐵 → ¬ (𝐴 < 𝐵𝐵 < 𝐴)))
10 reapval 8620 . . . 4 ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (𝐴 # 𝐵 ↔ (𝐴 < 𝐵𝐵 < 𝐴)))
1110notbid 668 . . 3 ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (¬ 𝐴 # 𝐵 ↔ ¬ (𝐴 < 𝐵𝐵 < 𝐴)))
129, 11sylibrd 169 . 2 ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (𝐴 = 𝐵 → ¬ 𝐴 # 𝐵))
13 axapti 8114 . . . 4 ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ ¬ (𝐴 < 𝐵𝐵 < 𝐴)) → 𝐴 = 𝐵)
14133expia 1207 . . 3 ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (¬ (𝐴 < 𝐵𝐵 < 𝐴) → 𝐴 = 𝐵))
1511, 14sylbid 150 . 2 ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (¬ 𝐴 # 𝐵𝐴 = 𝐵))
1612, 15impbid 129 1 ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (𝐴 = 𝐵 ↔ ¬ 𝐴 # 𝐵))
Colors of variables: wff set class
Syntax hints:  ¬ wn 3  wi 4  wa 104  wb 105  wo 709   = wceq 1364  wcel 2167   class class class wbr 4034  cr 7895   < clt 8078   # creap 8618
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 615  ax-in2 616  ax-io 710  ax-5 1461  ax-7 1462  ax-gen 1463  ax-ie1 1507  ax-ie2 1508  ax-8 1518  ax-10 1519  ax-11 1520  ax-i12 1521  ax-bndl 1523  ax-4 1524  ax-17 1540  ax-i9 1544  ax-ial 1548  ax-i5r 1549  ax-13 2169  ax-14 2170  ax-ext 2178  ax-sep 4152  ax-pow 4208  ax-pr 4243  ax-un 4469  ax-setind 4574  ax-cnex 7987  ax-resscn 7988  ax-pre-ltirr 8008  ax-pre-apti 8011
This theorem depends on definitions:  df-bi 117  df-3an 982  df-tru 1367  df-fal 1370  df-nf 1475  df-sb 1777  df-eu 2048  df-mo 2049  df-clab 2183  df-cleq 2189  df-clel 2192  df-nfc 2328  df-ne 2368  df-nel 2463  df-ral 2480  df-rex 2481  df-rab 2484  df-v 2765  df-dif 3159  df-un 3161  df-in 3163  df-ss 3170  df-pw 3608  df-sn 3629  df-pr 3630  df-op 3632  df-uni 3841  df-br 4035  df-opab 4096  df-xp 4670  df-pnf 8080  df-mnf 8081  df-ltxr 8083  df-reap 8619
This theorem is referenced by:  rimul  8629  apreap  8631  apti  8666
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