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Theorem cvnbtwn2 30073
Description: The covers relation implies no in-betweenness. (Contributed by NM, 12-Jun-2004.) (New usage is discouraged.)
Assertion
Ref Expression
cvnbtwn2 ((𝐴C𝐵C𝐶C ) → (𝐴 𝐵 → ((𝐴𝐶𝐶𝐵) → 𝐶 = 𝐵)))

Proof of Theorem cvnbtwn2
StepHypRef Expression
1 cvnbtwn 30072 . 2 ((𝐴C𝐵C𝐶C ) → (𝐴 𝐵 → ¬ (𝐴𝐶𝐶𝐵)))
2 iman 405 . . 3 (((𝐴𝐶𝐶𝐵) → 𝐶 = 𝐵) ↔ ¬ ((𝐴𝐶𝐶𝐵) ∧ ¬ 𝐶 = 𝐵))
3 anass 472 . . . . 5 (((𝐴𝐶𝐶𝐵) ∧ ¬ 𝐶 = 𝐵) ↔ (𝐴𝐶 ∧ (𝐶𝐵 ∧ ¬ 𝐶 = 𝐵)))
4 dfpss2 4016 . . . . . 6 (𝐶𝐵 ↔ (𝐶𝐵 ∧ ¬ 𝐶 = 𝐵))
54anbi2i 625 . . . . 5 ((𝐴𝐶𝐶𝐵) ↔ (𝐴𝐶 ∧ (𝐶𝐵 ∧ ¬ 𝐶 = 𝐵)))
63, 5bitr4i 281 . . . 4 (((𝐴𝐶𝐶𝐵) ∧ ¬ 𝐶 = 𝐵) ↔ (𝐴𝐶𝐶𝐵))
76notbii 323 . . 3 (¬ ((𝐴𝐶𝐶𝐵) ∧ ¬ 𝐶 = 𝐵) ↔ ¬ (𝐴𝐶𝐶𝐵))
82, 7bitr2i 279 . 2 (¬ (𝐴𝐶𝐶𝐵) ↔ ((𝐴𝐶𝐶𝐵) → 𝐶 = 𝐵))
91, 8syl6ib 254 1 ((𝐴C𝐵C𝐶C ) → (𝐴 𝐵 → ((𝐴𝐶𝐶𝐵) → 𝐶 = 𝐵)))
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wa 399  w3a 1084   = wceq 1538  wcel 2112  wss 3884  wpss 3885   class class class wbr 5033   C cch 28715   ccv 28750
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-pr 5298
This theorem depends on definitions:  df-bi 210  df-an 400  df-or 845  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-v 3446  df-dif 3887  df-un 3889  df-in 3891  df-ss 3901  df-pss 3903  df-nul 4247  df-if 4429  df-sn 4529  df-pr 4531  df-op 4535  df-br 5034  df-opab 5096  df-cv 30065
This theorem is referenced by:  cvati  30152  cvexchlem  30154  atexch  30167
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