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Theorem dfac2 8905
Description: Axiom of Choice (first form) of [Enderton] p. 49 implies of our Axiom of Choice (in the form of ac3 9236). The proof does not make use of AC. Note that the Axiom of Regularity is used by the proof. Specifically, elirrv 8456 and preleq 8466 that are referenced in the proof each make use of Regularity for their derivations. (The reverse implication can be derived without using Regularity; see dfac2a 8904.) TODO: Fix label in comment, and put label changes into list at top of set.mm. (Contributed by NM, 5-Apr-2004.) (Revised by Mario Carneiro, 26-Jun-2015.)
Assertion
Ref Expression
dfac2 (CHOICE ↔ ∀𝑥𝑦𝑧𝑥 (𝑧 ≠ ∅ → ∃!𝑤𝑧𝑣𝑦 (𝑧𝑣𝑤𝑣)))
Distinct variable group:   𝑥,𝑦,𝑧,𝑤,𝑣

Proof of Theorem dfac2
Dummy variables 𝑢 𝑓 𝑔 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 dfac3 8896 . . 3 (CHOICE ↔ ∀𝑥𝑓𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧))
2 nfra1 2936 . . . . . . 7 𝑧𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧)
3 rsp 2924 . . . . . . . . . . . . 13 (∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) → (𝑧𝑥 → (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧)))
4 equid 1936 . . . . . . . . . . . . . . . . . . 19 𝑧 = 𝑧
5 neeq1 2852 . . . . . . . . . . . . . . . . . . . . 21 (𝑢 = 𝑧 → (𝑢 ≠ ∅ ↔ 𝑧 ≠ ∅))
6 eqeq1 2625 . . . . . . . . . . . . . . . . . . . . 21 (𝑢 = 𝑧 → (𝑢 = 𝑧𝑧 = 𝑧))
75, 6anbi12d 746 . . . . . . . . . . . . . . . . . . . 20 (𝑢 = 𝑧 → ((𝑢 ≠ ∅ ∧ 𝑢 = 𝑧) ↔ (𝑧 ≠ ∅ ∧ 𝑧 = 𝑧)))
87rspcev 3298 . . . . . . . . . . . . . . . . . . 19 ((𝑧𝑥 ∧ (𝑧 ≠ ∅ ∧ 𝑧 = 𝑧)) → ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑢 = 𝑧))
94, 8mpanr2 719 . . . . . . . . . . . . . . . . . 18 ((𝑧𝑥𝑧 ≠ ∅) → ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑢 = 𝑧))
10 fveq2 6153 . . . . . . . . . . . . . . . . . . . . . 22 (𝑢 = 𝑧 → (𝑓𝑢) = (𝑓𝑧))
1110preq1d 4249 . . . . . . . . . . . . . . . . . . . . 21 (𝑢 = 𝑧 → {(𝑓𝑢), 𝑢} = {(𝑓𝑧), 𝑢})
12 preq2 4244 . . . . . . . . . . . . . . . . . . . . 21 (𝑢 = 𝑧 → {(𝑓𝑧), 𝑢} = {(𝑓𝑧), 𝑧})
1311, 12eqtr2d 2656 . . . . . . . . . . . . . . . . . . . 20 (𝑢 = 𝑧 → {(𝑓𝑧), 𝑧} = {(𝑓𝑢), 𝑢})
1413anim2i 592 . . . . . . . . . . . . . . . . . . 19 ((𝑢 ≠ ∅ ∧ 𝑢 = 𝑧) → (𝑢 ≠ ∅ ∧ {(𝑓𝑧), 𝑧} = {(𝑓𝑢), 𝑢}))
1514reximi 3006 . . . . . . . . . . . . . . . . . 18 (∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑢 = 𝑧) → ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ {(𝑓𝑧), 𝑧} = {(𝑓𝑢), 𝑢}))
169, 15syl 17 . . . . . . . . . . . . . . . . 17 ((𝑧𝑥𝑧 ≠ ∅) → ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ {(𝑓𝑧), 𝑧} = {(𝑓𝑢), 𝑢}))
17 prex 4875 . . . . . . . . . . . . . . . . . 18 {(𝑓𝑧), 𝑧} ∈ V
18 eqeq1 2625 . . . . . . . . . . . . . . . . . . . 20 (𝑔 = {(𝑓𝑧), 𝑧} → (𝑔 = {(𝑓𝑢), 𝑢} ↔ {(𝑓𝑧), 𝑧} = {(𝑓𝑢), 𝑢}))
1918anbi2d 739 . . . . . . . . . . . . . . . . . . 19 (𝑔 = {(𝑓𝑧), 𝑧} → ((𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢}) ↔ (𝑢 ≠ ∅ ∧ {(𝑓𝑧), 𝑧} = {(𝑓𝑢), 𝑢})))
2019rexbidv 3046 . . . . . . . . . . . . . . . . . 18 (𝑔 = {(𝑓𝑧), 𝑧} → (∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢}) ↔ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ {(𝑓𝑧), 𝑧} = {(𝑓𝑢), 𝑢})))
2117, 20elab 3337 . . . . . . . . . . . . . . . . 17 ({(𝑓𝑧), 𝑧} ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} ↔ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ {(𝑓𝑧), 𝑧} = {(𝑓𝑢), 𝑢}))
2216, 21sylibr 224 . . . . . . . . . . . . . . . 16 ((𝑧𝑥𝑧 ≠ ∅) → {(𝑓𝑧), 𝑧} ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})})
23 vex 3192 . . . . . . . . . . . . . . . . . 18 𝑧 ∈ V
2423prid2 4273 . . . . . . . . . . . . . . . . 17 𝑧 ∈ {(𝑓𝑧), 𝑧}
25 fvex 6163 . . . . . . . . . . . . . . . . . 18 (𝑓𝑧) ∈ V
2625prid1 4272 . . . . . . . . . . . . . . . . 17 (𝑓𝑧) ∈ {(𝑓𝑧), 𝑧}
2724, 26pm3.2i 471 . . . . . . . . . . . . . . . 16 (𝑧 ∈ {(𝑓𝑧), 𝑧} ∧ (𝑓𝑧) ∈ {(𝑓𝑧), 𝑧})
28 eleq2 2687 . . . . . . . . . . . . . . . . . 18 (𝑣 = {(𝑓𝑧), 𝑧} → (𝑧𝑣𝑧 ∈ {(𝑓𝑧), 𝑧}))
29 eleq2 2687 . . . . . . . . . . . . . . . . . 18 (𝑣 = {(𝑓𝑧), 𝑧} → ((𝑓𝑧) ∈ 𝑣 ↔ (𝑓𝑧) ∈ {(𝑓𝑧), 𝑧}))
3028, 29anbi12d 746 . . . . . . . . . . . . . . . . 17 (𝑣 = {(𝑓𝑧), 𝑧} → ((𝑧𝑣 ∧ (𝑓𝑧) ∈ 𝑣) ↔ (𝑧 ∈ {(𝑓𝑧), 𝑧} ∧ (𝑓𝑧) ∈ {(𝑓𝑧), 𝑧})))
3130rspcev 3298 . . . . . . . . . . . . . . . 16 (({(𝑓𝑧), 𝑧} ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} ∧ (𝑧 ∈ {(𝑓𝑧), 𝑧} ∧ (𝑓𝑧) ∈ {(𝑓𝑧), 𝑧})) → ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣 ∧ (𝑓𝑧) ∈ 𝑣))
3222, 27, 31sylancl 693 . . . . . . . . . . . . . . 15 ((𝑧𝑥𝑧 ≠ ∅) → ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣 ∧ (𝑓𝑧) ∈ 𝑣))
33 eleq1 2686 . . . . . . . . . . . . . . . . 17 (𝑤 = (𝑓𝑧) → (𝑤𝑧 ↔ (𝑓𝑧) ∈ 𝑧))
34 eleq1 2686 . . . . . . . . . . . . . . . . . . 19 (𝑤 = (𝑓𝑧) → (𝑤𝑣 ↔ (𝑓𝑧) ∈ 𝑣))
3534anbi2d 739 . . . . . . . . . . . . . . . . . 18 (𝑤 = (𝑓𝑧) → ((𝑧𝑣𝑤𝑣) ↔ (𝑧𝑣 ∧ (𝑓𝑧) ∈ 𝑣)))
3635rexbidv 3046 . . . . . . . . . . . . . . . . 17 (𝑤 = (𝑓𝑧) → (∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣) ↔ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣 ∧ (𝑓𝑧) ∈ 𝑣)))
3733, 36anbi12d 746 . . . . . . . . . . . . . . . 16 (𝑤 = (𝑓𝑧) → ((𝑤𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣)) ↔ ((𝑓𝑧) ∈ 𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣 ∧ (𝑓𝑧) ∈ 𝑣))))
3825, 37spcev 3289 . . . . . . . . . . . . . . 15 (((𝑓𝑧) ∈ 𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣 ∧ (𝑓𝑧) ∈ 𝑣)) → ∃𝑤(𝑤𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣)))
3932, 38sylan2 491 . . . . . . . . . . . . . 14 (((𝑓𝑧) ∈ 𝑧 ∧ (𝑧𝑥𝑧 ≠ ∅)) → ∃𝑤(𝑤𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣)))
4039ex 450 . . . . . . . . . . . . 13 ((𝑓𝑧) ∈ 𝑧 → ((𝑧𝑥𝑧 ≠ ∅) → ∃𝑤(𝑤𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣))))
413, 40syl8 76 . . . . . . . . . . . 12 (∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) → (𝑧𝑥 → (𝑧 ≠ ∅ → ((𝑧𝑥𝑧 ≠ ∅) → ∃𝑤(𝑤𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣))))))
4241impd 447 . . . . . . . . . . 11 (∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) → ((𝑧𝑥𝑧 ≠ ∅) → ((𝑧𝑥𝑧 ≠ ∅) → ∃𝑤(𝑤𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣)))))
4342pm2.43d 53 . . . . . . . . . 10 (∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) → ((𝑧𝑥𝑧 ≠ ∅) → ∃𝑤(𝑤𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣))))
44 df-rex 2913 . . . . . . . . . . . . . 14 (∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣) ↔ ∃𝑣(𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} ∧ (𝑧𝑣𝑤𝑣)))
45 vex 3192 . . . . . . . . . . . . . . . . . . . 20 𝑣 ∈ V
46 eqeq1 2625 . . . . . . . . . . . . . . . . . . . . . 22 (𝑔 = 𝑣 → (𝑔 = {(𝑓𝑢), 𝑢} ↔ 𝑣 = {(𝑓𝑢), 𝑢}))
4746anbi2d 739 . . . . . . . . . . . . . . . . . . . . 21 (𝑔 = 𝑣 → ((𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢}) ↔ (𝑢 ≠ ∅ ∧ 𝑣 = {(𝑓𝑢), 𝑢})))
4847rexbidv 3046 . . . . . . . . . . . . . . . . . . . 20 (𝑔 = 𝑣 → (∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢}) ↔ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑣 = {(𝑓𝑢), 𝑢})))
4945, 48elab 3337 . . . . . . . . . . . . . . . . . . 19 (𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} ↔ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑣 = {(𝑓𝑢), 𝑢}))
50 neeq1 2852 . . . . . . . . . . . . . . . . . . . . . . . . . . 27 (𝑧 = 𝑢 → (𝑧 ≠ ∅ ↔ 𝑢 ≠ ∅))
51 fveq2 6153 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 (𝑧 = 𝑢 → (𝑓𝑧) = (𝑓𝑢))
5251eleq1d 2683 . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 (𝑧 = 𝑢 → ((𝑓𝑧) ∈ 𝑧 ↔ (𝑓𝑢) ∈ 𝑧))
53 eleq2 2687 . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 (𝑧 = 𝑢 → ((𝑓𝑢) ∈ 𝑧 ↔ (𝑓𝑢) ∈ 𝑢))
5452, 53bitrd 268 . . . . . . . . . . . . . . . . . . . . . . . . . . 27 (𝑧 = 𝑢 → ((𝑓𝑧) ∈ 𝑧 ↔ (𝑓𝑢) ∈ 𝑢))
5550, 54imbi12d 334 . . . . . . . . . . . . . . . . . . . . . . . . . 26 (𝑧 = 𝑢 → ((𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) ↔ (𝑢 ≠ ∅ → (𝑓𝑢) ∈ 𝑢)))
5655rspccv 3295 . . . . . . . . . . . . . . . . . . . . . . . . 25 (∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) → (𝑢𝑥 → (𝑢 ≠ ∅ → (𝑓𝑢) ∈ 𝑢)))
57 elirrv 8456 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 ¬ 𝑤𝑤
58 eleq2 2687 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 (𝑤 = 𝑧 → (𝑤𝑤𝑤𝑧))
5957, 58mtbii 316 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 (𝑤 = 𝑧 → ¬ 𝑤𝑧)
6059con2i 134 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 (𝑤𝑧 → ¬ 𝑤 = 𝑧)
61 vex 3192 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 𝑤 ∈ V
62 fvex 6163 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 (𝑓𝑢) ∈ V
63 vex 3192 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 𝑢 ∈ V
6461, 23, 62, 63prel12 4356 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 𝑤 = 𝑧 → ({𝑤, 𝑧} = {(𝑓𝑢), 𝑢} ↔ (𝑤 ∈ {(𝑓𝑢), 𝑢} ∧ 𝑧 ∈ {(𝑓𝑢), 𝑢})))
65 ancom 466 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 ((𝑤𝑣𝑧𝑣) ↔ (𝑧𝑣𝑤𝑣))
66 eleq2 2687 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 (𝑣 = {(𝑓𝑢), 𝑢} → (𝑤𝑣𝑤 ∈ {(𝑓𝑢), 𝑢}))
67 eleq2 2687 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 (𝑣 = {(𝑓𝑢), 𝑢} → (𝑧𝑣𝑧 ∈ {(𝑓𝑢), 𝑢}))
6866, 67anbi12d 746 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 (𝑣 = {(𝑓𝑢), 𝑢} → ((𝑤𝑣𝑧𝑣) ↔ (𝑤 ∈ {(𝑓𝑢), 𝑢} ∧ 𝑧 ∈ {(𝑓𝑢), 𝑢})))
6965, 68syl5rbbr 275 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 (𝑣 = {(𝑓𝑢), 𝑢} → ((𝑤 ∈ {(𝑓𝑢), 𝑢} ∧ 𝑧 ∈ {(𝑓𝑢), 𝑢}) ↔ (𝑧𝑣𝑤𝑣)))
7064, 69sylan9bbr 736 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 ((𝑣 = {(𝑓𝑢), 𝑢} ∧ ¬ 𝑤 = 𝑧) → ({𝑤, 𝑧} = {(𝑓𝑢), 𝑢} ↔ (𝑧𝑣𝑤𝑣)))
7160, 70sylan2 491 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 ((𝑣 = {(𝑓𝑢), 𝑢} ∧ 𝑤𝑧) → ({𝑤, 𝑧} = {(𝑓𝑢), 𝑢} ↔ (𝑧𝑣𝑤𝑣)))
7271adantrr 752 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 ((𝑣 = {(𝑓𝑢), 𝑢} ∧ (𝑤𝑧 ∧ (𝑓𝑢) ∈ 𝑢)) → ({𝑤, 𝑧} = {(𝑓𝑢), 𝑢} ↔ (𝑧𝑣𝑤𝑣)))
7372pm5.32da 672 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 (𝑣 = {(𝑓𝑢), 𝑢} → (((𝑤𝑧 ∧ (𝑓𝑢) ∈ 𝑢) ∧ {𝑤, 𝑧} = {(𝑓𝑢), 𝑢}) ↔ ((𝑤𝑧 ∧ (𝑓𝑢) ∈ 𝑢) ∧ (𝑧𝑣𝑤𝑣))))
7461, 23, 62, 63preleq 8466 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 (((𝑤𝑧 ∧ (𝑓𝑢) ∈ 𝑢) ∧ {𝑤, 𝑧} = {(𝑓𝑢), 𝑢}) → (𝑤 = (𝑓𝑢) ∧ 𝑧 = 𝑢))
7573, 74syl6bir 244 . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 (𝑣 = {(𝑓𝑢), 𝑢} → (((𝑤𝑧 ∧ (𝑓𝑢) ∈ 𝑢) ∧ (𝑧𝑣𝑤𝑣)) → (𝑤 = (𝑓𝑢) ∧ 𝑧 = 𝑢)))
7651eqeq2d 2631 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 (𝑧 = 𝑢 → (𝑤 = (𝑓𝑧) ↔ 𝑤 = (𝑓𝑢)))
7776biimparc 504 . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 ((𝑤 = (𝑓𝑢) ∧ 𝑧 = 𝑢) → 𝑤 = (𝑓𝑧))
7875, 77syl6 35 . . . . . . . . . . . . . . . . . . . . . . . . . . 27 (𝑣 = {(𝑓𝑢), 𝑢} → (((𝑤𝑧 ∧ (𝑓𝑢) ∈ 𝑢) ∧ (𝑧𝑣𝑤𝑣)) → 𝑤 = (𝑓𝑧)))
7978exp4c 635 . . . . . . . . . . . . . . . . . . . . . . . . . 26 (𝑣 = {(𝑓𝑢), 𝑢} → (𝑤𝑧 → ((𝑓𝑢) ∈ 𝑢 → ((𝑧𝑣𝑤𝑣) → 𝑤 = (𝑓𝑧)))))
8079com13 88 . . . . . . . . . . . . . . . . . . . . . . . . 25 ((𝑓𝑢) ∈ 𝑢 → (𝑤𝑧 → (𝑣 = {(𝑓𝑢), 𝑢} → ((𝑧𝑣𝑤𝑣) → 𝑤 = (𝑓𝑧)))))
8156, 80syl8 76 . . . . . . . . . . . . . . . . . . . . . . . 24 (∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) → (𝑢𝑥 → (𝑢 ≠ ∅ → (𝑤𝑧 → (𝑣 = {(𝑓𝑢), 𝑢} → ((𝑧𝑣𝑤𝑣) → 𝑤 = (𝑓𝑧)))))))
8281com4r 94 . . . . . . . . . . . . . . . . . . . . . . 23 (𝑤𝑧 → (∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) → (𝑢𝑥 → (𝑢 ≠ ∅ → (𝑣 = {(𝑓𝑢), 𝑢} → ((𝑧𝑣𝑤𝑣) → 𝑤 = (𝑓𝑧)))))))
8382imp 445 . . . . . . . . . . . . . . . . . . . . . 22 ((𝑤𝑧 ∧ ∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧)) → (𝑢𝑥 → (𝑢 ≠ ∅ → (𝑣 = {(𝑓𝑢), 𝑢} → ((𝑧𝑣𝑤𝑣) → 𝑤 = (𝑓𝑧))))))
8483imp4a 613 . . . . . . . . . . . . . . . . . . . . 21 ((𝑤𝑧 ∧ ∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧)) → (𝑢𝑥 → ((𝑢 ≠ ∅ ∧ 𝑣 = {(𝑓𝑢), 𝑢}) → ((𝑧𝑣𝑤𝑣) → 𝑤 = (𝑓𝑧)))))
8584com3l 89 . . . . . . . . . . . . . . . . . . . 20 (𝑢𝑥 → ((𝑢 ≠ ∅ ∧ 𝑣 = {(𝑓𝑢), 𝑢}) → ((𝑤𝑧 ∧ ∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧)) → ((𝑧𝑣𝑤𝑣) → 𝑤 = (𝑓𝑧)))))
8685rexlimiv 3021 . . . . . . . . . . . . . . . . . . 19 (∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑣 = {(𝑓𝑢), 𝑢}) → ((𝑤𝑧 ∧ ∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧)) → ((𝑧𝑣𝑤𝑣) → 𝑤 = (𝑓𝑧))))
8749, 86sylbi 207 . . . . . . . . . . . . . . . . . 18 (𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} → ((𝑤𝑧 ∧ ∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧)) → ((𝑧𝑣𝑤𝑣) → 𝑤 = (𝑓𝑧))))
8887expd 452 . . . . . . . . . . . . . . . . 17 (𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} → (𝑤𝑧 → (∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) → ((𝑧𝑣𝑤𝑣) → 𝑤 = (𝑓𝑧)))))
8988com13 88 . . . . . . . . . . . . . . . 16 (∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) → (𝑤𝑧 → (𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} → ((𝑧𝑣𝑤𝑣) → 𝑤 = (𝑓𝑧)))))
9089imp4b 612 . . . . . . . . . . . . . . 15 ((∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) ∧ 𝑤𝑧) → ((𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} ∧ (𝑧𝑣𝑤𝑣)) → 𝑤 = (𝑓𝑧)))
9190exlimdv 1858 . . . . . . . . . . . . . 14 ((∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) ∧ 𝑤𝑧) → (∃𝑣(𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} ∧ (𝑧𝑣𝑤𝑣)) → 𝑤 = (𝑓𝑧)))
9244, 91syl5bi 232 . . . . . . . . . . . . 13 ((∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) ∧ 𝑤𝑧) → (∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣) → 𝑤 = (𝑓𝑧)))
9392expimpd 628 . . . . . . . . . . . 12 (∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) → ((𝑤𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣)) → 𝑤 = (𝑓𝑧)))
9493alrimiv 1852 . . . . . . . . . . 11 (∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) → ∀𝑤((𝑤𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣)) → 𝑤 = (𝑓𝑧)))
95 mo2icl 3371 . . . . . . . . . . 11 (∀𝑤((𝑤𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣)) → 𝑤 = (𝑓𝑧)) → ∃*𝑤(𝑤𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣)))
9694, 95syl 17 . . . . . . . . . 10 (∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) → ∃*𝑤(𝑤𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣)))
9743, 96jctird 566 . . . . . . . . 9 (∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) → ((𝑧𝑥𝑧 ≠ ∅) → (∃𝑤(𝑤𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣)) ∧ ∃*𝑤(𝑤𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣)))))
98 df-reu 2914 . . . . . . . . . 10 (∃!𝑤𝑧𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣) ↔ ∃!𝑤(𝑤𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣)))
99 eu5 2495 . . . . . . . . . 10 (∃!𝑤(𝑤𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣)) ↔ (∃𝑤(𝑤𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣)) ∧ ∃*𝑤(𝑤𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣))))
10098, 99bitri 264 . . . . . . . . 9 (∃!𝑤𝑧𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣) ↔ (∃𝑤(𝑤𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣)) ∧ ∃*𝑤(𝑤𝑧 ∧ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣))))
10197, 100syl6ibr 242 . . . . . . . 8 (∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) → ((𝑧𝑥𝑧 ≠ ∅) → ∃!𝑤𝑧𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣)))
102101expd 452 . . . . . . 7 (∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) → (𝑧𝑥 → (𝑧 ≠ ∅ → ∃!𝑤𝑧𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣))))
1032, 102ralrimi 2952 . . . . . 6 (∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) → ∀𝑧𝑥 (𝑧 ≠ ∅ → ∃!𝑤𝑧𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣)))
104 vex 3192 . . . . . . . . . . . 12 𝑓 ∈ V
105104rnex 7054 . . . . . . . . . . 11 ran 𝑓 ∈ V
106 p0ex 4818 . . . . . . . . . . 11 {∅} ∈ V
107105, 106unex 6916 . . . . . . . . . 10 (ran 𝑓 ∪ {∅}) ∈ V
108 vex 3192 . . . . . . . . . 10 𝑥 ∈ V
109107, 108unex 6916 . . . . . . . . 9 ((ran 𝑓 ∪ {∅}) ∪ 𝑥) ∈ V
110109pwex 4813 . . . . . . . 8 𝒫 ((ran 𝑓 ∪ {∅}) ∪ 𝑥) ∈ V
111 ssun1 3759 . . . . . . . . . . . . . . 15 (ran 𝑓 ∪ {∅}) ⊆ ((ran 𝑓 ∪ {∅}) ∪ 𝑥)
112 fvrn0 6178 . . . . . . . . . . . . . . 15 (𝑓𝑢) ∈ (ran 𝑓 ∪ {∅})
113111, 112sselii 3584 . . . . . . . . . . . . . 14 (𝑓𝑢) ∈ ((ran 𝑓 ∪ {∅}) ∪ 𝑥)
114 elun2 3764 . . . . . . . . . . . . . 14 (𝑢𝑥𝑢 ∈ ((ran 𝑓 ∪ {∅}) ∪ 𝑥))
115 prssi 4326 . . . . . . . . . . . . . 14 (((𝑓𝑢) ∈ ((ran 𝑓 ∪ {∅}) ∪ 𝑥) ∧ 𝑢 ∈ ((ran 𝑓 ∪ {∅}) ∪ 𝑥)) → {(𝑓𝑢), 𝑢} ⊆ ((ran 𝑓 ∪ {∅}) ∪ 𝑥))
116113, 114, 115sylancr 694 . . . . . . . . . . . . 13 (𝑢𝑥 → {(𝑓𝑢), 𝑢} ⊆ ((ran 𝑓 ∪ {∅}) ∪ 𝑥))
117 prex 4875 . . . . . . . . . . . . . 14 {(𝑓𝑢), 𝑢} ∈ V
118117elpw 4141 . . . . . . . . . . . . 13 ({(𝑓𝑢), 𝑢} ∈ 𝒫 ((ran 𝑓 ∪ {∅}) ∪ 𝑥) ↔ {(𝑓𝑢), 𝑢} ⊆ ((ran 𝑓 ∪ {∅}) ∪ 𝑥))
119116, 118sylibr 224 . . . . . . . . . . . 12 (𝑢𝑥 → {(𝑓𝑢), 𝑢} ∈ 𝒫 ((ran 𝑓 ∪ {∅}) ∪ 𝑥))
120 eleq1 2686 . . . . . . . . . . . 12 (𝑔 = {(𝑓𝑢), 𝑢} → (𝑔 ∈ 𝒫 ((ran 𝑓 ∪ {∅}) ∪ 𝑥) ↔ {(𝑓𝑢), 𝑢} ∈ 𝒫 ((ran 𝑓 ∪ {∅}) ∪ 𝑥)))
121119, 120syl5ibrcom 237 . . . . . . . . . . 11 (𝑢𝑥 → (𝑔 = {(𝑓𝑢), 𝑢} → 𝑔 ∈ 𝒫 ((ran 𝑓 ∪ {∅}) ∪ 𝑥)))
122121adantld 483 . . . . . . . . . 10 (𝑢𝑥 → ((𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢}) → 𝑔 ∈ 𝒫 ((ran 𝑓 ∪ {∅}) ∪ 𝑥)))
123122rexlimiv 3021 . . . . . . . . 9 (∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢}) → 𝑔 ∈ 𝒫 ((ran 𝑓 ∪ {∅}) ∪ 𝑥))
124123abssi 3661 . . . . . . . 8 {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} ⊆ 𝒫 ((ran 𝑓 ∪ {∅}) ∪ 𝑥)
125110, 124ssexi 4768 . . . . . . 7 {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} ∈ V
126 rexeq 3131 . . . . . . . . . 10 (𝑦 = {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} → (∃𝑣𝑦 (𝑧𝑣𝑤𝑣) ↔ ∃𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣)))
127126reubidv 3118 . . . . . . . . 9 (𝑦 = {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} → (∃!𝑤𝑧𝑣𝑦 (𝑧𝑣𝑤𝑣) ↔ ∃!𝑤𝑧𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣)))
128127imbi2d 330 . . . . . . . 8 (𝑦 = {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} → ((𝑧 ≠ ∅ → ∃!𝑤𝑧𝑣𝑦 (𝑧𝑣𝑤𝑣)) ↔ (𝑧 ≠ ∅ → ∃!𝑤𝑧𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣))))
129128ralbidv 2981 . . . . . . 7 (𝑦 = {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} → (∀𝑧𝑥 (𝑧 ≠ ∅ → ∃!𝑤𝑧𝑣𝑦 (𝑧𝑣𝑤𝑣)) ↔ ∀𝑧𝑥 (𝑧 ≠ ∅ → ∃!𝑤𝑧𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣))))
130125, 129spcev 3289 . . . . . 6 (∀𝑧𝑥 (𝑧 ≠ ∅ → ∃!𝑤𝑧𝑣 ∈ {𝑔 ∣ ∃𝑢𝑥 (𝑢 ≠ ∅ ∧ 𝑔 = {(𝑓𝑢), 𝑢})} (𝑧𝑣𝑤𝑣)) → ∃𝑦𝑧𝑥 (𝑧 ≠ ∅ → ∃!𝑤𝑧𝑣𝑦 (𝑧𝑣𝑤𝑣)))
131103, 130syl 17 . . . . 5 (∀𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) → ∃𝑦𝑧𝑥 (𝑧 ≠ ∅ → ∃!𝑤𝑧𝑣𝑦 (𝑧𝑣𝑤𝑣)))
132131exlimiv 1855 . . . 4 (∃𝑓𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) → ∃𝑦𝑧𝑥 (𝑧 ≠ ∅ → ∃!𝑤𝑧𝑣𝑦 (𝑧𝑣𝑤𝑣)))
133132alimi 1736 . . 3 (∀𝑥𝑓𝑧𝑥 (𝑧 ≠ ∅ → (𝑓𝑧) ∈ 𝑧) → ∀𝑥𝑦𝑧𝑥 (𝑧 ≠ ∅ → ∃!𝑤𝑧𝑣𝑦 (𝑧𝑣𝑤𝑣)))
1341, 133sylbi 207 . 2 (CHOICE → ∀𝑥𝑦𝑧𝑥 (𝑧 ≠ ∅ → ∃!𝑤𝑧𝑣𝑦 (𝑧𝑣𝑤𝑣)))
135 dfac2a 8904 . 2 (∀𝑥𝑦𝑧𝑥 (𝑧 ≠ ∅ → ∃!𝑤𝑧𝑣𝑦 (𝑧𝑣𝑤𝑣)) → CHOICE)
136134, 135impbii 199 1 (CHOICE ↔ ∀𝑥𝑦𝑧𝑥 (𝑧 ≠ ∅ → ∃!𝑤𝑧𝑣𝑦 (𝑧𝑣𝑤𝑣)))
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wb 196  wa 384  wal 1478   = wceq 1480  wex 1701  wcel 1987  ∃!weu 2469  ∃*wmo 2470  {cab 2607  wne 2790  wral 2907  wrex 2908  ∃!wreu 2909  cun 3557  wss 3559  c0 3896  𝒫 cpw 4135  {csn 4153  {cpr 4155  ran crn 5080  cfv 5852  CHOICEwac 8890
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1719  ax-4 1734  ax-5 1836  ax-6 1885  ax-7 1932  ax-8 1989  ax-9 1996  ax-10 2016  ax-11 2031  ax-12 2044  ax-13 2245  ax-ext 2601  ax-sep 4746  ax-nul 4754  ax-pow 4808  ax-pr 4872  ax-un 6909  ax-reg 8449
This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3an 1038  df-tru 1483  df-ex 1702  df-nf 1707  df-sb 1878  df-eu 2473  df-mo 2474  df-clab 2608  df-cleq 2614  df-clel 2617  df-nfc 2750  df-ne 2791  df-ral 2912  df-rex 2913  df-reu 2914  df-rab 2916  df-v 3191  df-sbc 3422  df-dif 3562  df-un 3564  df-in 3566  df-ss 3573  df-nul 3897  df-if 4064  df-pw 4137  df-sn 4154  df-pr 4156  df-op 4160  df-uni 4408  df-br 4619  df-opab 4679  df-mpt 4680  df-eprel 4990  df-id 4994  df-fr 5038  df-xp 5085  df-rel 5086  df-cnv 5087  df-co 5088  df-dm 5089  df-rn 5090  df-res 5091  df-ima 5092  df-iota 5815  df-fun 5854  df-fn 5855  df-f 5856  df-fv 5860  df-riota 6571  df-ac 8891
This theorem is referenced by:  dfac7  8906
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