Theorem brprcneu 6872

Description: If 𝐴 is a proper class and 𝐹 is any class, then there is no unique set which is related to 𝐴 through the binary relation 𝐹. See brprcneuALT 6873 for a proof that uses ax-pow 5337 instead of ax-pr 5405. (Contributed by Scott Fenton, 7-Oct-2017.)

Assertion

Ref	Expression
brprcneu	⊢ (¬ 𝐴 ∈ V → ¬ ∃!𝑥 𝐴𝐹𝑥)

Distinct variable groups:   𝑥,𝐴   𝑥,𝐹

Proof of Theorem brprcneu

Dummy variable 𝑦 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		dtru 5419	. . . . . . . . 9 ⊢ ¬ ∀𝑦 𝑦 = 𝑥
2		exnal 1854	. . . . . . . . . 10 ⊢ (∃𝑦 ¬ 𝑥 = 𝑦 ↔ ¬ ∀𝑦 𝑥 = 𝑦)
3		equcom 2045	. . . . . . . . . . 11 ⊢ (𝑥 = 𝑦 ↔ 𝑦 = 𝑥)
4	3	albii 1846	. . . . . . . . . 10 ⊢ (∀𝑦 𝑥 = 𝑦 ↔ ∀𝑦 𝑦 = 𝑥)
5	2, 4	xchbinx 337	. . . . . . . . 9 ⊢ (∃𝑦 ¬ 𝑥 = 𝑦 ↔ ¬ ∀𝑦 𝑦 = 𝑥)
6	1, 5	mpbir 234	. . . . . . . 8 ⊢ ∃𝑦 ¬ 𝑥 = 𝑦
7	6	jctr 533	. . . . . . 7 ⊢ (∅ ∈ 𝐹 → (∅ ∈ 𝐹 ∧ ∃𝑦 ¬ 𝑥 = 𝑦))
8		19.42v 1980	. . . . . . 7 ⊢ (∃𝑦(∅ ∈ 𝐹 ∧ ¬ 𝑥 = 𝑦) ↔ (∅ ∈ 𝐹 ∧ ∃𝑦 ¬ 𝑥 = 𝑦))
9	7, 8	sylibr 237	. . . . . 6 ⊢ (∅ ∈ 𝐹 → ∃𝑦(∅ ∈ 𝐹 ∧ ¬ 𝑥 = 𝑦))
10		opprc1 4866	. . . . . . . 8 ⊢ (¬ 𝐴 ∈ V → ⟨𝐴, 𝑥⟩ = ∅)
11	10	eleq1d 2854	. . . . . . 7 ⊢ (¬ 𝐴 ∈ V → (⟨𝐴, 𝑥⟩ ∈ 𝐹 ↔ ∅ ∈ 𝐹))
12		opprc1 4866	. . . . . . . . . . . 12 ⊢ (¬ 𝐴 ∈ V → ⟨𝐴, 𝑦⟩ = ∅)
13	12	eleq1d 2854	. . . . . . . . . . 11 ⊢ (¬ 𝐴 ∈ V → (⟨𝐴, 𝑦⟩ ∈ 𝐹 ↔ ∅ ∈ 𝐹))
14	11, 13	anbi12d 643	. . . . . . . . . 10 ⊢ (¬ 𝐴 ∈ V → ((⟨𝐴, 𝑥⟩ ∈ 𝐹 ∧ ⟨𝐴, 𝑦⟩ ∈ 𝐹) ↔ (∅ ∈ 𝐹 ∧ ∅ ∈ 𝐹)))
15		anidm 574	. . . . . . . . . 10 ⊢ ((∅ ∈ 𝐹 ∧ ∅ ∈ 𝐹) ↔ ∅ ∈ 𝐹)
16	14, 15	bitrdi 290	. . . . . . . . 9 ⊢ (¬ 𝐴 ∈ V → ((⟨𝐴, 𝑥⟩ ∈ 𝐹 ∧ ⟨𝐴, 𝑦⟩ ∈ 𝐹) ↔ ∅ ∈ 𝐹))
17	16	anbi1d 642	. . . . . . . 8 ⊢ (¬ 𝐴 ∈ V → (((⟨𝐴, 𝑥⟩ ∈ 𝐹 ∧ ⟨𝐴, 𝑦⟩ ∈ 𝐹) ∧ ¬ 𝑥 = 𝑦) ↔ (∅ ∈ 𝐹 ∧ ¬ 𝑥 = 𝑦)))
18	17	exbidv 1948	. . . . . . 7 ⊢ (¬ 𝐴 ∈ V → (∃𝑦((⟨𝐴, 𝑥⟩ ∈ 𝐹 ∧ ⟨𝐴, 𝑦⟩ ∈ 𝐹) ∧ ¬ 𝑥 = 𝑦) ↔ ∃𝑦(∅ ∈ 𝐹 ∧ ¬ 𝑥 = 𝑦)))
19	11, 18	imbi12d 347	. . . . . 6 ⊢ (¬ 𝐴 ∈ V → ((⟨𝐴, 𝑥⟩ ∈ 𝐹 → ∃𝑦((⟨𝐴, 𝑥⟩ ∈ 𝐹 ∧ ⟨𝐴, 𝑦⟩ ∈ 𝐹) ∧ ¬ 𝑥 = 𝑦)) ↔ (∅ ∈ 𝐹 → ∃𝑦(∅ ∈ 𝐹 ∧ ¬ 𝑥 = 𝑦))))
20	9, 19	mpbiri 261	. . . . 5 ⊢ (¬ 𝐴 ∈ V → (⟨𝐴, 𝑥⟩ ∈ 𝐹 → ∃𝑦((⟨𝐴, 𝑥⟩ ∈ 𝐹 ∧ ⟨𝐴, 𝑦⟩ ∈ 𝐹) ∧ ¬ 𝑥 = 𝑦)))
21		df-br 5114	. . . . 5 ⊢ (𝐴𝐹𝑥 ↔ ⟨𝐴, 𝑥⟩ ∈ 𝐹)
22		df-br 5114	. . . . . . . 8 ⊢ (𝐴𝐹𝑦 ↔ ⟨𝐴, 𝑦⟩ ∈ 𝐹)
23	21, 22	anbi12i 639	. . . . . . 7 ⊢ ((𝐴𝐹𝑥 ∧ 𝐴𝐹𝑦) ↔ (⟨𝐴, 𝑥⟩ ∈ 𝐹 ∧ ⟨𝐴, 𝑦⟩ ∈ 𝐹))
24	23	anbi1i 635	. . . . . 6 ⊢ (((𝐴𝐹𝑥 ∧ 𝐴𝐹𝑦) ∧ ¬ 𝑥 = 𝑦) ↔ ((⟨𝐴, 𝑥⟩ ∈ 𝐹 ∧ ⟨𝐴, 𝑦⟩ ∈ 𝐹) ∧ ¬ 𝑥 = 𝑦))
25	24	exbii 1875	. . . . 5 ⊢ (∃𝑦((𝐴𝐹𝑥 ∧ 𝐴𝐹𝑦) ∧ ¬ 𝑥 = 𝑦) ↔ ∃𝑦((⟨𝐴, 𝑥⟩ ∈ 𝐹 ∧ ⟨𝐴, 𝑦⟩ ∈ 𝐹) ∧ ¬ 𝑥 = 𝑦))
26	20, 21, 25	3imtr4g 299	. . . 4 ⊢ (¬ 𝐴 ∈ V → (𝐴𝐹𝑥 → ∃𝑦((𝐴𝐹𝑥 ∧ 𝐴𝐹𝑦) ∧ ¬ 𝑥 = 𝑦)))
27	26	eximdv 1944	. . 3 ⊢ (¬ 𝐴 ∈ V → (∃𝑥 𝐴𝐹𝑥 → ∃𝑥∃𝑦((𝐴𝐹𝑥 ∧ 𝐴𝐹𝑦) ∧ ¬ 𝑥 = 𝑦)))
28		exnal 1854	. . . 4 ⊢ (∃𝑥 ¬ ∀𝑦((𝐴𝐹𝑥 ∧ 𝐴𝐹𝑦) → 𝑥 = 𝑦) ↔ ¬ ∀𝑥∀𝑦((𝐴𝐹𝑥 ∧ 𝐴𝐹𝑦) → 𝑥 = 𝑦))
29		exanali 1886	. . . . 5 ⊢ (∃𝑦((𝐴𝐹𝑥 ∧ 𝐴𝐹𝑦) ∧ ¬ 𝑥 = 𝑦) ↔ ¬ ∀𝑦((𝐴𝐹𝑥 ∧ 𝐴𝐹𝑦) → 𝑥 = 𝑦))
30	29	exbii 1875	. . . 4 ⊢ (∃𝑥∃𝑦((𝐴𝐹𝑥 ∧ 𝐴𝐹𝑦) ∧ ¬ 𝑥 = 𝑦) ↔ ∃𝑥 ¬ ∀𝑦((𝐴𝐹𝑥 ∧ 𝐴𝐹𝑦) → 𝑥 = 𝑦))
31		breq2 5117	. . . . . 6 ⊢ (𝑥 = 𝑦 → (𝐴𝐹𝑥 ↔ 𝐴𝐹𝑦))
32	31	mo4 2600	. . . . 5 ⊢ (∃*𝑥 𝐴𝐹𝑥 ↔ ∀𝑥∀𝑦((𝐴𝐹𝑥 ∧ 𝐴𝐹𝑦) → 𝑥 = 𝑦))
33	32	notbii 323	. . . 4 ⊢ (¬ ∃*𝑥 𝐴𝐹𝑥 ↔ ¬ ∀𝑥∀𝑦((𝐴𝐹𝑥 ∧ 𝐴𝐹𝑦) → 𝑥 = 𝑦))
34	28, 30, 33	3bitr4ri 307	. . 3 ⊢ (¬ ∃*𝑥 𝐴𝐹𝑥 ↔ ∃𝑥∃𝑦((𝐴𝐹𝑥 ∧ 𝐴𝐹𝑦) ∧ ¬ 𝑥 = 𝑦))
35	27, 34	imbitrrdi 255	. 2 ⊢ (¬ 𝐴 ∈ V → (∃𝑥 𝐴𝐹𝑥 → ¬ ∃*𝑥 𝐴𝐹𝑥))
36		df-eu 2603	. . . 4 ⊢ (∃!𝑥 𝐴𝐹𝑥 ↔ (∃𝑥 𝐴𝐹𝑥 ∧ ∃*𝑥 𝐴𝐹𝑥))
37	36	notbii 323	. . 3 ⊢ (¬ ∃!𝑥 𝐴𝐹𝑥 ↔ ¬ (∃𝑥 𝐴𝐹𝑥 ∧ ∃*𝑥 𝐴𝐹𝑥))
38		imnan 404	. . 3 ⊢ ((∃𝑥 𝐴𝐹𝑥 → ¬ ∃*𝑥 𝐴𝐹𝑥) ↔ ¬ (∃𝑥 𝐴𝐹𝑥 ∧ ∃*𝑥 𝐴𝐹𝑥))
39	37, 38	bitr4i 281	. 2 ⊢ (¬ ∃!𝑥 𝐴𝐹𝑥 ↔ (∃𝑥 𝐴𝐹𝑥 → ¬ ∃*𝑥 𝐴𝐹𝑥))
40	35, 39	sylibr 237	1 ⊢ (¬ 𝐴 ∈ V → ¬ ∃!𝑥 𝐴𝐹𝑥)

Syntax hints:  ¬ wn 3   → wi 4   ∧ wa 400  ∀wal 1565  ∃wex 1806   ∈ wcel 2149  ∃*wmo 2571  ∃!weu 2602  Vcvv 3463  ∅c0 4294  ⟨cop 4600   class class class wbr 5113

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1822  ax-4 1836  ax-5 1937  ax-6 1994  ax-7 2035  ax-8 2151  ax-9 2159  ax-ext 2741  ax-nul 5271  ax-pr 5405

This theorem depends on definitions:  df-bi 210  df-an 401  df-or 861  df-3an 1103  df-tru 1570  df-fal 1580  df-ex 1807  df-sb 2098  df-mo 2573  df-eu 2603  df-clab 2748  df-cleq 2761  df-clel 2844  df-rab 3424  df-v 3465  df-dif 3916  df-un 3918  df-ss 3930  df-nul 4295  df-if 4493  df-sn 4595  df-pr 4597  df-op 4601  df-br 5114

This theorem is referenced by:  fvprc  6874  eubrv  47661