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Theorem isplig 28265
 Description: The predicate "is a planar incidence geometry" for sets. (Contributed by FL, 2-Aug-2009.)
Hypothesis
Ref Expression
isplig.1 𝑃 = 𝐺
Assertion
Ref Expression
isplig (𝐺𝐴 → (𝐺 ∈ Plig ↔ (∀𝑎𝑃𝑏𝑃 (𝑎𝑏 → ∃!𝑙𝐺 (𝑎𝑙𝑏𝑙)) ∧ ∀𝑙𝐺𝑎𝑃𝑏𝑃 (𝑎𝑏𝑎𝑙𝑏𝑙) ∧ ∃𝑎𝑃𝑏𝑃𝑐𝑃𝑙𝐺 ¬ (𝑎𝑙𝑏𝑙𝑐𝑙))))
Distinct variable groups:   𝑎,𝑏,𝑐,𝑙,𝐺   𝑃,𝑎,𝑏,𝑐
Allowed substitution hints:   𝐴(𝑎,𝑏,𝑐,𝑙)   𝑃(𝑙)

Proof of Theorem isplig
Dummy variable 𝑥 is distinct from all other variables.
StepHypRef Expression
1 unieq 4836 . . . . 5 (𝑥 = 𝐺 𝑥 = 𝐺)
2 isplig.1 . . . . 5 𝑃 = 𝐺
31, 2syl6eqr 2877 . . . 4 (𝑥 = 𝐺 𝑥 = 𝑃)
4 reueq1 3399 . . . . . 6 (𝑥 = 𝐺 → (∃!𝑙𝑥 (𝑎𝑙𝑏𝑙) ↔ ∃!𝑙𝐺 (𝑎𝑙𝑏𝑙)))
54imbi2d 344 . . . . 5 (𝑥 = 𝐺 → ((𝑎𝑏 → ∃!𝑙𝑥 (𝑎𝑙𝑏𝑙)) ↔ (𝑎𝑏 → ∃!𝑙𝐺 (𝑎𝑙𝑏𝑙))))
63, 5raleqbidv 3393 . . . 4 (𝑥 = 𝐺 → (∀𝑏 𝑥(𝑎𝑏 → ∃!𝑙𝑥 (𝑎𝑙𝑏𝑙)) ↔ ∀𝑏𝑃 (𝑎𝑏 → ∃!𝑙𝐺 (𝑎𝑙𝑏𝑙))))
73, 6raleqbidv 3393 . . 3 (𝑥 = 𝐺 → (∀𝑎 𝑥𝑏 𝑥(𝑎𝑏 → ∃!𝑙𝑥 (𝑎𝑙𝑏𝑙)) ↔ ∀𝑎𝑃𝑏𝑃 (𝑎𝑏 → ∃!𝑙𝐺 (𝑎𝑙𝑏𝑙))))
83rexeqdv 3404 . . . . 5 (𝑥 = 𝐺 → (∃𝑏 𝑥(𝑎𝑏𝑎𝑙𝑏𝑙) ↔ ∃𝑏𝑃 (𝑎𝑏𝑎𝑙𝑏𝑙)))
93, 8rexeqbidv 3394 . . . 4 (𝑥 = 𝐺 → (∃𝑎 𝑥𝑏 𝑥(𝑎𝑏𝑎𝑙𝑏𝑙) ↔ ∃𝑎𝑃𝑏𝑃 (𝑎𝑏𝑎𝑙𝑏𝑙)))
109raleqbi1dv 3395 . . 3 (𝑥 = 𝐺 → (∀𝑙𝑥𝑎 𝑥𝑏 𝑥(𝑎𝑏𝑎𝑙𝑏𝑙) ↔ ∀𝑙𝐺𝑎𝑃𝑏𝑃 (𝑎𝑏𝑎𝑙𝑏𝑙)))
11 raleq 3397 . . . . . 6 (𝑥 = 𝐺 → (∀𝑙𝑥 ¬ (𝑎𝑙𝑏𝑙𝑐𝑙) ↔ ∀𝑙𝐺 ¬ (𝑎𝑙𝑏𝑙𝑐𝑙)))
123, 11rexeqbidv 3394 . . . . 5 (𝑥 = 𝐺 → (∃𝑐 𝑥𝑙𝑥 ¬ (𝑎𝑙𝑏𝑙𝑐𝑙) ↔ ∃𝑐𝑃𝑙𝐺 ¬ (𝑎𝑙𝑏𝑙𝑐𝑙)))
133, 12rexeqbidv 3394 . . . 4 (𝑥 = 𝐺 → (∃𝑏 𝑥𝑐 𝑥𝑙𝑥 ¬ (𝑎𝑙𝑏𝑙𝑐𝑙) ↔ ∃𝑏𝑃𝑐𝑃𝑙𝐺 ¬ (𝑎𝑙𝑏𝑙𝑐𝑙)))
143, 13rexeqbidv 3394 . . 3 (𝑥 = 𝐺 → (∃𝑎 𝑥𝑏 𝑥𝑐 𝑥𝑙𝑥 ¬ (𝑎𝑙𝑏𝑙𝑐𝑙) ↔ ∃𝑎𝑃𝑏𝑃𝑐𝑃𝑙𝐺 ¬ (𝑎𝑙𝑏𝑙𝑐𝑙)))
157, 10, 143anbi123d 1433 . 2 (𝑥 = 𝐺 → ((∀𝑎 𝑥𝑏 𝑥(𝑎𝑏 → ∃!𝑙𝑥 (𝑎𝑙𝑏𝑙)) ∧ ∀𝑙𝑥𝑎 𝑥𝑏 𝑥(𝑎𝑏𝑎𝑙𝑏𝑙) ∧ ∃𝑎 𝑥𝑏 𝑥𝑐 𝑥𝑙𝑥 ¬ (𝑎𝑙𝑏𝑙𝑐𝑙)) ↔ (∀𝑎𝑃𝑏𝑃 (𝑎𝑏 → ∃!𝑙𝐺 (𝑎𝑙𝑏𝑙)) ∧ ∀𝑙𝐺𝑎𝑃𝑏𝑃 (𝑎𝑏𝑎𝑙𝑏𝑙) ∧ ∃𝑎𝑃𝑏𝑃𝑐𝑃𝑙𝐺 ¬ (𝑎𝑙𝑏𝑙𝑐𝑙))))
16 df-plig 28264 . 2 Plig = {𝑥 ∣ (∀𝑎 𝑥𝑏 𝑥(𝑎𝑏 → ∃!𝑙𝑥 (𝑎𝑙𝑏𝑙)) ∧ ∀𝑙𝑥𝑎 𝑥𝑏 𝑥(𝑎𝑏𝑎𝑙𝑏𝑙) ∧ ∃𝑎 𝑥𝑏 𝑥𝑐 𝑥𝑙𝑥 ¬ (𝑎𝑙𝑏𝑙𝑐𝑙))}
1715, 16elab2g 3655 1 (𝐺𝐴 → (𝐺 ∈ Plig ↔ (∀𝑎𝑃𝑏𝑃 (𝑎𝑏 → ∃!𝑙𝐺 (𝑎𝑙𝑏𝑙)) ∧ ∀𝑙𝐺𝑎𝑃𝑏𝑃 (𝑎𝑏𝑎𝑙𝑏𝑙) ∧ ∃𝑎𝑃𝑏𝑃𝑐𝑃𝑙𝐺 ¬ (𝑎𝑙𝑏𝑙𝑐𝑙))))
 Colors of variables: wff setvar class Syntax hints:  ¬ wn 3   → wi 4   ↔ wb 209   ∧ wa 399   ∧ w3a 1084   = wceq 1538   ∈ wcel 2115   ≠ wne 3014  ∀wral 3133  ∃wrex 3134  ∃!wreu 3135  ∪ cuni 4825  Pligcplig 28263 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 1912  ax-6 1971  ax-7 2016  ax-8 2117  ax-9 2125  ax-10 2146  ax-11 2162  ax-12 2179  ax-ext 2796 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 2071  df-mo 2624  df-eu 2655  df-clab 2803  df-cleq 2817  df-clel 2896  df-nfc 2964  df-ral 3138  df-rex 3139  df-reu 3140  df-v 3483  df-in 3927  df-ss 3937  df-uni 4826  df-plig 28264 This theorem is referenced by:  ispligb  28266  tncp  28267  l2p  28268  eulplig  28274
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