Theorem gblacfnacd 35092

Description: If 𝐹 is a global choice function, then the Axiom of Choice (in the form of the right-hand side of dfac4 10160) holds. Note that 𝐹 must be a proper class by fndmexb 7929. This means we cannot show that the existence of a class that behaves as a global choice function is sufficient because we only have existential quantifiers for sets, not (proper) classes. However, if a class variant of exlimiv 1928 were available, then it could be used alongside the closed form of this theorem to prove that result. (Contributed by BTernaryTau, 12-Dec-2024.)

Hypotheses

Ref	Expression
gblacfnacd.1	⊢ (𝜑 → 𝐹 Fn V)
gblacfnacd.2	⊢ (𝜑 → ∀𝑧(𝑧 ≠ ∅ → (𝐹‘𝑧) ∈ 𝑧))

Assertion

Ref	Expression
gblacfnacd	⊢ (𝜑 → ∀𝑥∃𝑓(𝑓 Fn 𝑥 ∧ ∀𝑧 ∈ 𝑥 (𝑧 ≠ ∅ → (𝑓‘𝑧) ∈ 𝑧)))

Distinct variable groups:   𝑥,𝑓   𝜑,𝑥,𝑧   𝑓,𝐹,𝑧

Allowed substitution hints:   𝜑(𝑓)   𝐹(𝑥)

Proof of Theorem gblacfnacd

Step	Hyp	Ref	Expression
1		gblacfnacd.1	. . . 4 ⊢ (𝜑 → 𝐹 Fn V)
2		fnfun 6669	. . . 4 ⊢ (𝐹 Fn V → Fun 𝐹)
3		resfunexg 7235	. . . . 5 ⊢ ((Fun 𝐹 ∧ 𝑥 ∈ V) → (𝐹 ↾ 𝑥) ∈ V)
4	3	elvd 3484	. . . 4 ⊢ (Fun 𝐹 → (𝐹 ↾ 𝑥) ∈ V)
5	1, 2, 4	3syl 18	. . 3 ⊢ (𝜑 → (𝐹 ↾ 𝑥) ∈ V)
6		ssv 4020	. . . . 5 ⊢ 𝑥 ⊆ V
7		fnssres 6692	. . . . 5 ⊢ ((𝐹 Fn V ∧ 𝑥 ⊆ V) → (𝐹 ↾ 𝑥) Fn 𝑥)
8	1, 6, 7	sylancl 586	. . . 4 ⊢ (𝜑 → (𝐹 ↾ 𝑥) Fn 𝑥)
9		gblacfnacd.2	. . . . . . 7 ⊢ (𝜑 → ∀𝑧(𝑧 ≠ ∅ → (𝐹‘𝑧) ∈ 𝑧))
10	9	19.21bi 2187	. . . . . 6 ⊢ (𝜑 → (𝑧 ≠ ∅ → (𝐹‘𝑧) ∈ 𝑧))
11		fvres 6926	. . . . . . . 8 ⊢ (𝑧 ∈ 𝑥 → ((𝐹 ↾ 𝑥)‘𝑧) = (𝐹‘𝑧))
12	11	eleq1d 2824	. . . . . . 7 ⊢ (𝑧 ∈ 𝑥 → (((𝐹 ↾ 𝑥)‘𝑧) ∈ 𝑧 ↔ (𝐹‘𝑧) ∈ 𝑧))
13	12	imbi2d 340	. . . . . 6 ⊢ (𝑧 ∈ 𝑥 → ((𝑧 ≠ ∅ → ((𝐹 ↾ 𝑥)‘𝑧) ∈ 𝑧) ↔ (𝑧 ≠ ∅ → (𝐹‘𝑧) ∈ 𝑧)))
14	10, 13	syl5ibrcom 247	. . . . 5 ⊢ (𝜑 → (𝑧 ∈ 𝑥 → (𝑧 ≠ ∅ → ((𝐹 ↾ 𝑥)‘𝑧) ∈ 𝑧)))
15	14	ralrimiv 3143	. . . 4 ⊢ (𝜑 → ∀𝑧 ∈ 𝑥 (𝑧 ≠ ∅ → ((𝐹 ↾ 𝑥)‘𝑧) ∈ 𝑧))
16	8, 15	jca 511	. . 3 ⊢ (𝜑 → ((𝐹 ↾ 𝑥) Fn 𝑥 ∧ ∀𝑧 ∈ 𝑥 (𝑧 ≠ ∅ → ((𝐹 ↾ 𝑥)‘𝑧) ∈ 𝑧)))
17		fneq1 6660	. . . 4 ⊢ (𝑓 = (𝐹 ↾ 𝑥) → (𝑓 Fn 𝑥 ↔ (𝐹 ↾ 𝑥) Fn 𝑥))
18		fveq1 6906	. . . . . . 7 ⊢ (𝑓 = (𝐹 ↾ 𝑥) → (𝑓‘𝑧) = ((𝐹 ↾ 𝑥)‘𝑧))
19	18	eleq1d 2824	. . . . . 6 ⊢ (𝑓 = (𝐹 ↾ 𝑥) → ((𝑓‘𝑧) ∈ 𝑧 ↔ ((𝐹 ↾ 𝑥)‘𝑧) ∈ 𝑧))
20	19	imbi2d 340	. . . . 5 ⊢ (𝑓 = (𝐹 ↾ 𝑥) → ((𝑧 ≠ ∅ → (𝑓‘𝑧) ∈ 𝑧) ↔ (𝑧 ≠ ∅ → ((𝐹 ↾ 𝑥)‘𝑧) ∈ 𝑧)))
21	20	ralbidv 3176	. . . 4 ⊢ (𝑓 = (𝐹 ↾ 𝑥) → (∀𝑧 ∈ 𝑥 (𝑧 ≠ ∅ → (𝑓‘𝑧) ∈ 𝑧) ↔ ∀𝑧 ∈ 𝑥 (𝑧 ≠ ∅ → ((𝐹 ↾ 𝑥)‘𝑧) ∈ 𝑧)))
22	17, 21	anbi12d 632	. . 3 ⊢ (𝑓 = (𝐹 ↾ 𝑥) → ((𝑓 Fn 𝑥 ∧ ∀𝑧 ∈ 𝑥 (𝑧 ≠ ∅ → (𝑓‘𝑧) ∈ 𝑧)) ↔ ((𝐹 ↾ 𝑥) Fn 𝑥 ∧ ∀𝑧 ∈ 𝑥 (𝑧 ≠ ∅ → ((𝐹 ↾ 𝑥)‘𝑧) ∈ 𝑧))))
23	5, 16, 22	spcedv 3598	. 2 ⊢ (𝜑 → ∃𝑓(𝑓 Fn 𝑥 ∧ ∀𝑧 ∈ 𝑥 (𝑧 ≠ ∅ → (𝑓‘𝑧) ∈ 𝑧)))
24	23	alrimiv 1925	1 ⊢ (𝜑 → ∀𝑥∃𝑓(𝑓 Fn 𝑥 ∧ ∀𝑧 ∈ 𝑥 (𝑧 ≠ ∅ → (𝑓‘𝑧) ∈ 𝑧)))

Syntax hints:   → wi 4   ∧ wa 395  ∀wal 1535   = wceq 1537  ∃wex 1776   ∈ wcel 2106   ≠ wne 2938  ∀wral 3059  Vcvv 3478   ⊆ wss 3963  ∅c0 4339   ↾ cres 5691  Fun wfun 6557   Fn wfn 6558  ‘cfv 6563

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1792  ax-4 1806  ax-5 1908  ax-6 1965  ax-7 2005  ax-8 2108  ax-9 2116  ax-10 2139  ax-11 2155  ax-12 2175  ax-ext 2706  ax-rep 5285  ax-sep 5302  ax-nul 5312  ax-pr 5438

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3an 1088  df-tru 1540  df-fal 1550  df-ex 1777  df-nf 1781  df-sb 2063  df-mo 2538  df-eu 2567  df-clab 2713  df-cleq 2727  df-clel 2814  df-nfc 2890  df-ne 2939  df-ral 3060  df-rex 3069  df-reu 3379  df-rab 3434  df-v 3480  df-sbc 3792  df-csb 3909  df-dif 3966  df-un 3968  df-in 3970  df-ss 3980  df-nul 4340  df-if 4532  df-sn 4632  df-pr 4634  df-op 4638  df-uni 4913  df-iun 4998  df-br 5149  df-opab 5211  df-mpt 5232  df-id 5583  df-xp 5695  df-rel 5696  df-cnv 5697  df-co 5698  df-dm 5699  df-rn 5700  df-res 5701  df-ima 5702  df-iota 6516  df-fun 6565  df-fn 6566  df-f 6567  df-f1 6568  df-fo 6569  df-f1o 6570  df-fv 6571

This theorem is referenced by: (None)