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Theorem fununi 6600
Description: The union of a chain (with respect to inclusion) of functions is a function. (Contributed by NM, 10-Aug-2004.)
Assertion
Ref Expression
fununi (∀𝑓𝐴 (Fun 𝑓 ∧ ∀𝑔𝐴 (𝑓𝑔𝑔𝑓)) → Fun 𝐴)
Distinct variable group:   𝑓,𝑔,𝐴

Proof of Theorem fununi
Dummy variables 𝑥 𝑦 𝑧 𝑣 𝑤 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 funrel 6542 . . . . 5 (Fun 𝑓 → Rel 𝑓)
21adantr 485 . . . 4 ((Fun 𝑓 ∧ ∀𝑔𝐴 (𝑓𝑔𝑔𝑓)) → Rel 𝑓)
32ralimi 3102 . . 3 (∀𝑓𝐴 (Fun 𝑓 ∧ ∀𝑔𝐴 (𝑓𝑔𝑔𝑓)) → ∀𝑓𝐴 Rel 𝑓)
4 reluni 5796 . . 3 (Rel 𝐴 ↔ ∀𝑓𝐴 Rel 𝑓)
53, 4sylibr 237 . 2 (∀𝑓𝐴 (Fun 𝑓 ∧ ∀𝑔𝐴 (𝑓𝑔𝑔𝑓)) → Rel 𝐴)
6 r19.28v 3196 . . . 4 ((Fun 𝑓 ∧ ∀𝑔𝐴 (𝑓𝑔𝑔𝑓)) → ∀𝑔𝐴 (Fun 𝑓 ∧ (𝑓𝑔𝑔𝑓)))
76ralimi 3102 . . 3 (∀𝑓𝐴 (Fun 𝑓 ∧ ∀𝑔𝐴 (𝑓𝑔𝑔𝑓)) → ∀𝑓𝐴𝑔𝐴 (Fun 𝑓 ∧ (𝑓𝑔𝑔𝑓)))
8 ssel 3933 . . . . . . . . . . . 12 (𝑤𝑣 → (⟨𝑥, 𝑦⟩ ∈ 𝑤 → ⟨𝑥, 𝑦⟩ ∈ 𝑣))
98anim1d 622 . . . . . . . . . . 11 (𝑤𝑣 → ((⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣) → (⟨𝑥, 𝑦⟩ ∈ 𝑣 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣)))
10 dffun4 6538 . . . . . . . . . . . . . 14 (Fun 𝑣 ↔ (Rel 𝑣 ∧ ∀𝑥𝑦𝑧((⟨𝑥, 𝑦⟩ ∈ 𝑣 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣) → 𝑦 = 𝑧)))
1110simprbi 502 . . . . . . . . . . . . 13 (Fun 𝑣 → ∀𝑥𝑦𝑧((⟨𝑥, 𝑦⟩ ∈ 𝑣 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣) → 𝑦 = 𝑧))
121119.21bbi 2228 . . . . . . . . . . . 12 (Fun 𝑣 → ∀𝑧((⟨𝑥, 𝑦⟩ ∈ 𝑣 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣) → 𝑦 = 𝑧))
131219.21bi 2227 . . . . . . . . . . 11 (Fun 𝑣 → ((⟨𝑥, 𝑦⟩ ∈ 𝑣 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣) → 𝑦 = 𝑧))
149, 13syl9r 79 . . . . . . . . . 10 (Fun 𝑣 → (𝑤𝑣 → ((⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣) → 𝑦 = 𝑧)))
1514adantl 486 . . . . . . . . 9 ((Fun 𝑤 ∧ Fun 𝑣) → (𝑤𝑣 → ((⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣) → 𝑦 = 𝑧)))
16 ssel 3933 . . . . . . . . . . . 12 (𝑣𝑤 → (⟨𝑥, 𝑧⟩ ∈ 𝑣 → ⟨𝑥, 𝑧⟩ ∈ 𝑤))
1716anim2d 623 . . . . . . . . . . 11 (𝑣𝑤 → ((⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣) → (⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑤)))
18 dffun4 6538 . . . . . . . . . . . . . 14 (Fun 𝑤 ↔ (Rel 𝑤 ∧ ∀𝑥𝑦𝑧((⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑤) → 𝑦 = 𝑧)))
1918simprbi 502 . . . . . . . . . . . . 13 (Fun 𝑤 → ∀𝑥𝑦𝑧((⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑤) → 𝑦 = 𝑧))
201919.21bbi 2228 . . . . . . . . . . . 12 (Fun 𝑤 → ∀𝑧((⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑤) → 𝑦 = 𝑧))
212019.21bi 2227 . . . . . . . . . . 11 (Fun 𝑤 → ((⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑤) → 𝑦 = 𝑧))
2217, 21syl9r 79 . . . . . . . . . 10 (Fun 𝑤 → (𝑣𝑤 → ((⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣) → 𝑦 = 𝑧)))
2322adantr 485 . . . . . . . . 9 ((Fun 𝑤 ∧ Fun 𝑣) → (𝑣𝑤 → ((⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣) → 𝑦 = 𝑧)))
2415, 23jaod 872 . . . . . . . 8 ((Fun 𝑤 ∧ Fun 𝑣) → ((𝑤𝑣𝑣𝑤) → ((⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣) → 𝑦 = 𝑧)))
2524imp 411 . . . . . . 7 (((Fun 𝑤 ∧ Fun 𝑣) ∧ (𝑤𝑣𝑣𝑤)) → ((⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣) → 𝑦 = 𝑧))
26252ralimi 3135 . . . . . 6 (∀𝑤𝐴𝑣𝐴 ((Fun 𝑤 ∧ Fun 𝑣) ∧ (𝑤𝑣𝑣𝑤)) → ∀𝑤𝐴𝑣𝐴 ((⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣) → 𝑦 = 𝑧))
27 funeq 6545 . . . . . . . . . 10 (𝑓 = 𝑤 → (Fun 𝑓 ↔ Fun 𝑤))
28 sseq1 3964 . . . . . . . . . . 11 (𝑓 = 𝑤 → (𝑓𝑔𝑤𝑔))
29 sseq2 3965 . . . . . . . . . . 11 (𝑓 = 𝑤 → (𝑔𝑓𝑔𝑤))
3028, 29orbi12d 931 . . . . . . . . . 10 (𝑓 = 𝑤 → ((𝑓𝑔𝑔𝑓) ↔ (𝑤𝑔𝑔𝑤)))
3127, 30anbi12d 643 . . . . . . . . 9 (𝑓 = 𝑤 → ((Fun 𝑓 ∧ (𝑓𝑔𝑔𝑓)) ↔ (Fun 𝑤 ∧ (𝑤𝑔𝑔𝑤))))
32 sseq2 3965 . . . . . . . . . . 11 (𝑔 = 𝑣 → (𝑤𝑔𝑤𝑣))
33 sseq1 3964 . . . . . . . . . . 11 (𝑔 = 𝑣 → (𝑔𝑤𝑣𝑤))
3432, 33orbi12d 931 . . . . . . . . . 10 (𝑔 = 𝑣 → ((𝑤𝑔𝑔𝑤) ↔ (𝑤𝑣𝑣𝑤)))
3534anbi2d 641 . . . . . . . . 9 (𝑔 = 𝑣 → ((Fun 𝑤 ∧ (𝑤𝑔𝑔𝑤)) ↔ (Fun 𝑤 ∧ (𝑤𝑣𝑣𝑤))))
3631, 35cbvral2vw 3247 . . . . . . . 8 (∀𝑓𝐴𝑔𝐴 (Fun 𝑓 ∧ (𝑓𝑔𝑔𝑓)) ↔ ∀𝑤𝐴𝑣𝐴 (Fun 𝑤 ∧ (𝑤𝑣𝑣𝑤)))
37 ralcom 3293 . . . . . . . . 9 (∀𝑓𝐴𝑔𝐴 (Fun 𝑓 ∧ (𝑓𝑔𝑔𝑓)) ↔ ∀𝑔𝐴𝑓𝐴 (Fun 𝑓 ∧ (𝑓𝑔𝑔𝑓)))
38 orcom 883 . . . . . . . . . . . 12 ((𝑓𝑔𝑔𝑓) ↔ (𝑔𝑓𝑓𝑔))
39 sseq1 3964 . . . . . . . . . . . . 13 (𝑔 = 𝑤 → (𝑔𝑓𝑤𝑓))
40 sseq2 3965 . . . . . . . . . . . . 13 (𝑔 = 𝑤 → (𝑓𝑔𝑓𝑤))
4139, 40orbi12d 931 . . . . . . . . . . . 12 (𝑔 = 𝑤 → ((𝑔𝑓𝑓𝑔) ↔ (𝑤𝑓𝑓𝑤)))
4238, 41bitrid 286 . . . . . . . . . . 11 (𝑔 = 𝑤 → ((𝑓𝑔𝑔𝑓) ↔ (𝑤𝑓𝑓𝑤)))
4342anbi2d 641 . . . . . . . . . 10 (𝑔 = 𝑤 → ((Fun 𝑓 ∧ (𝑓𝑔𝑔𝑓)) ↔ (Fun 𝑓 ∧ (𝑤𝑓𝑓𝑤))))
44 funeq 6545 . . . . . . . . . . 11 (𝑓 = 𝑣 → (Fun 𝑓 ↔ Fun 𝑣))
45 sseq2 3965 . . . . . . . . . . . 12 (𝑓 = 𝑣 → (𝑤𝑓𝑤𝑣))
46 sseq1 3964 . . . . . . . . . . . 12 (𝑓 = 𝑣 → (𝑓𝑤𝑣𝑤))
4745, 46orbi12d 931 . . . . . . . . . . 11 (𝑓 = 𝑣 → ((𝑤𝑓𝑓𝑤) ↔ (𝑤𝑣𝑣𝑤)))
4844, 47anbi12d 643 . . . . . . . . . 10 (𝑓 = 𝑣 → ((Fun 𝑓 ∧ (𝑤𝑓𝑓𝑤)) ↔ (Fun 𝑣 ∧ (𝑤𝑣𝑣𝑤))))
4943, 48cbvral2vw 3247 . . . . . . . . 9 (∀𝑔𝐴𝑓𝐴 (Fun 𝑓 ∧ (𝑓𝑔𝑔𝑓)) ↔ ∀𝑤𝐴𝑣𝐴 (Fun 𝑣 ∧ (𝑤𝑣𝑣𝑤)))
5037, 49bitri 278 . . . . . . . 8 (∀𝑓𝐴𝑔𝐴 (Fun 𝑓 ∧ (𝑓𝑔𝑔𝑓)) ↔ ∀𝑤𝐴𝑣𝐴 (Fun 𝑣 ∧ (𝑤𝑣𝑣𝑤)))
5136, 50anbi12i 639 . . . . . . 7 ((∀𝑓𝐴𝑔𝐴 (Fun 𝑓 ∧ (𝑓𝑔𝑔𝑓)) ∧ ∀𝑓𝐴𝑔𝐴 (Fun 𝑓 ∧ (𝑓𝑔𝑔𝑓))) ↔ (∀𝑤𝐴𝑣𝐴 (Fun 𝑤 ∧ (𝑤𝑣𝑣𝑤)) ∧ ∀𝑤𝐴𝑣𝐴 (Fun 𝑣 ∧ (𝑤𝑣𝑣𝑤))))
52 anidm 574 . . . . . . 7 ((∀𝑓𝐴𝑔𝐴 (Fun 𝑓 ∧ (𝑓𝑔𝑔𝑓)) ∧ ∀𝑓𝐴𝑔𝐴 (Fun 𝑓 ∧ (𝑓𝑔𝑔𝑓))) ↔ ∀𝑓𝐴𝑔𝐴 (Fun 𝑓 ∧ (𝑓𝑔𝑔𝑓)))
53 anandir 689 . . . . . . . . 9 (((Fun 𝑤 ∧ Fun 𝑣) ∧ (𝑤𝑣𝑣𝑤)) ↔ ((Fun 𝑤 ∧ (𝑤𝑣𝑣𝑤)) ∧ (Fun 𝑣 ∧ (𝑤𝑣𝑣𝑤))))
54532ralbii 3140 . . . . . . . 8 (∀𝑤𝐴𝑣𝐴 ((Fun 𝑤 ∧ Fun 𝑣) ∧ (𝑤𝑣𝑣𝑤)) ↔ ∀𝑤𝐴𝑣𝐴 ((Fun 𝑤 ∧ (𝑤𝑣𝑣𝑤)) ∧ (Fun 𝑣 ∧ (𝑤𝑣𝑣𝑤))))
55 r19.26-2 3150 . . . . . . . 8 (∀𝑤𝐴𝑣𝐴 ((Fun 𝑤 ∧ (𝑤𝑣𝑣𝑤)) ∧ (Fun 𝑣 ∧ (𝑤𝑣𝑣𝑤))) ↔ (∀𝑤𝐴𝑣𝐴 (Fun 𝑤 ∧ (𝑤𝑣𝑣𝑤)) ∧ ∀𝑤𝐴𝑣𝐴 (Fun 𝑣 ∧ (𝑤𝑣𝑣𝑤))))
5654, 55bitr2i 279 . . . . . . 7 ((∀𝑤𝐴𝑣𝐴 (Fun 𝑤 ∧ (𝑤𝑣𝑣𝑤)) ∧ ∀𝑤𝐴𝑣𝐴 (Fun 𝑣 ∧ (𝑤𝑣𝑣𝑤))) ↔ ∀𝑤𝐴𝑣𝐴 ((Fun 𝑤 ∧ Fun 𝑣) ∧ (𝑤𝑣𝑣𝑤)))
5751, 52, 563bitr3i 304 . . . . . 6 (∀𝑓𝐴𝑔𝐴 (Fun 𝑓 ∧ (𝑓𝑔𝑔𝑓)) ↔ ∀𝑤𝐴𝑣𝐴 ((Fun 𝑤 ∧ Fun 𝑣) ∧ (𝑤𝑣𝑣𝑤)))
58 eluni 4871 . . . . . . . . . 10 (⟨𝑥, 𝑦⟩ ∈ 𝐴 ↔ ∃𝑤(⟨𝑥, 𝑦⟩ ∈ 𝑤𝑤𝐴))
59 eluni 4871 . . . . . . . . . 10 (⟨𝑥, 𝑧⟩ ∈ 𝐴 ↔ ∃𝑣(⟨𝑥, 𝑧⟩ ∈ 𝑣𝑣𝐴))
6058, 59anbi12i 639 . . . . . . . . 9 ((⟨𝑥, 𝑦⟩ ∈ 𝐴 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝐴) ↔ (∃𝑤(⟨𝑥, 𝑦⟩ ∈ 𝑤𝑤𝐴) ∧ ∃𝑣(⟨𝑥, 𝑧⟩ ∈ 𝑣𝑣𝐴)))
61 exdistrv 1978 . . . . . . . . 9 (∃𝑤𝑣((⟨𝑥, 𝑦⟩ ∈ 𝑤𝑤𝐴) ∧ (⟨𝑥, 𝑧⟩ ∈ 𝑣𝑣𝐴)) ↔ (∃𝑤(⟨𝑥, 𝑦⟩ ∈ 𝑤𝑤𝐴) ∧ ∃𝑣(⟨𝑥, 𝑧⟩ ∈ 𝑣𝑣𝐴)))
62 an4 668 . . . . . . . . . . 11 (((⟨𝑥, 𝑦⟩ ∈ 𝑤𝑤𝐴) ∧ (⟨𝑥, 𝑧⟩ ∈ 𝑣𝑣𝐴)) ↔ ((⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣) ∧ (𝑤𝐴𝑣𝐴)))
6362biancomi 467 . . . . . . . . . 10 (((⟨𝑥, 𝑦⟩ ∈ 𝑤𝑤𝐴) ∧ (⟨𝑥, 𝑧⟩ ∈ 𝑣𝑣𝐴)) ↔ ((𝑤𝐴𝑣𝐴) ∧ (⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣)))
64632exbii 1872 . . . . . . . . 9 (∃𝑤𝑣((⟨𝑥, 𝑦⟩ ∈ 𝑤𝑤𝐴) ∧ (⟨𝑥, 𝑧⟩ ∈ 𝑣𝑣𝐴)) ↔ ∃𝑤𝑣((𝑤𝐴𝑣𝐴) ∧ (⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣)))
6560, 61, 643bitr2i 302 . . . . . . . 8 ((⟨𝑥, 𝑦⟩ ∈ 𝐴 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝐴) ↔ ∃𝑤𝑣((𝑤𝐴𝑣𝐴) ∧ (⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣)))
6665imbi1i 352 . . . . . . 7 (((⟨𝑥, 𝑦⟩ ∈ 𝐴 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝐴) → 𝑦 = 𝑧) ↔ (∃𝑤𝑣((𝑤𝐴𝑣𝐴) ∧ (⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣)) → 𝑦 = 𝑧))
67 19.23v 1965 . . . . . . 7 (∀𝑤(∃𝑣((𝑤𝐴𝑣𝐴) ∧ (⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣)) → 𝑦 = 𝑧) ↔ (∃𝑤𝑣((𝑤𝐴𝑣𝐴) ∧ (⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣)) → 𝑦 = 𝑧))
68 r2al 3201 . . . . . . . 8 (∀𝑤𝐴𝑣𝐴 ((⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣) → 𝑦 = 𝑧) ↔ ∀𝑤𝑣((𝑤𝐴𝑣𝐴) → ((⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣) → 𝑦 = 𝑧)))
69 impexp 455 . . . . . . . . 9 ((((𝑤𝐴𝑣𝐴) ∧ (⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣)) → 𝑦 = 𝑧) ↔ ((𝑤𝐴𝑣𝐴) → ((⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣) → 𝑦 = 𝑧)))
70692albii 1843 . . . . . . . 8 (∀𝑤𝑣(((𝑤𝐴𝑣𝐴) ∧ (⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣)) → 𝑦 = 𝑧) ↔ ∀𝑤𝑣((𝑤𝐴𝑣𝐴) → ((⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣) → 𝑦 = 𝑧)))
71 19.23v 1965 . . . . . . . . 9 (∀𝑣(((𝑤𝐴𝑣𝐴) ∧ (⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣)) → 𝑦 = 𝑧) ↔ (∃𝑣((𝑤𝐴𝑣𝐴) ∧ (⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣)) → 𝑦 = 𝑧))
7271albii 1842 . . . . . . . 8 (∀𝑤𝑣(((𝑤𝐴𝑣𝐴) ∧ (⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣)) → 𝑦 = 𝑧) ↔ ∀𝑤(∃𝑣((𝑤𝐴𝑣𝐴) ∧ (⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣)) → 𝑦 = 𝑧))
7368, 70, 723bitr2ri 303 . . . . . . 7 (∀𝑤(∃𝑣((𝑤𝐴𝑣𝐴) ∧ (⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣)) → 𝑦 = 𝑧) ↔ ∀𝑤𝐴𝑣𝐴 ((⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣) → 𝑦 = 𝑧))
7466, 67, 733bitr2i 302 . . . . . 6 (((⟨𝑥, 𝑦⟩ ∈ 𝐴 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝐴) → 𝑦 = 𝑧) ↔ ∀𝑤𝐴𝑣𝐴 ((⟨𝑥, 𝑦⟩ ∈ 𝑤 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝑣) → 𝑦 = 𝑧))
7526, 57, 743imtr4i 295 . . . . 5 (∀𝑓𝐴𝑔𝐴 (Fun 𝑓 ∧ (𝑓𝑔𝑔𝑓)) → ((⟨𝑥, 𝑦⟩ ∈ 𝐴 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝐴) → 𝑦 = 𝑧))
7675alrimiv 1950 . . . 4 (∀𝑓𝐴𝑔𝐴 (Fun 𝑓 ∧ (𝑓𝑔𝑔𝑓)) → ∀𝑧((⟨𝑥, 𝑦⟩ ∈ 𝐴 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝐴) → 𝑦 = 𝑧))
7776alrimivv 1951 . . 3 (∀𝑓𝐴𝑔𝐴 (Fun 𝑓 ∧ (𝑓𝑔𝑔𝑓)) → ∀𝑥𝑦𝑧((⟨𝑥, 𝑦⟩ ∈ 𝐴 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝐴) → 𝑦 = 𝑧))
787, 77syl 18 . 2 (∀𝑓𝐴 (Fun 𝑓 ∧ ∀𝑔𝐴 (𝑓𝑔𝑔𝑓)) → ∀𝑥𝑦𝑧((⟨𝑥, 𝑦⟩ ∈ 𝐴 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝐴) → 𝑦 = 𝑧))
79 dffun4 6538 . 2 (Fun 𝐴 ↔ (Rel 𝐴 ∧ ∀𝑥𝑦𝑧((⟨𝑥, 𝑦⟩ ∈ 𝐴 ∧ ⟨𝑥, 𝑧⟩ ∈ 𝐴) → 𝑦 = 𝑧)))
805, 78, 79sylanbrc 594 1 (∀𝑓𝐴 (Fun 𝑓 ∧ ∀𝑔𝐴 (𝑓𝑔𝑔𝑓)) → Fun 𝐴)
Colors of variables: wff setvar class
Syntax hints:  wi 4  wa 400  wo 860  wal 1561  wex 1802  wcel 2145  wral 3079  wss 3907  cop 4591   cuni 4868  Rel wrel 5657  Fun wfun 6519
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1818  ax-4 1832  ax-5 1933  ax-6 1990  ax-7 2031  ax-8 2147  ax-9 2155  ax-11 2194  ax-12 2215  ax-ext 2737  ax-sep 5251  ax-pr 5395
This theorem depends on definitions:  df-bi 210  df-an 401  df-or 861  df-3an 1103  df-tru 1566  df-fal 1576  df-ex 1803  df-sb 2094  df-clab 2744  df-cleq 2757  df-clel 2840  df-ral 3080  df-rex 3090  df-rab 3418  df-v 3459  df-dif 3910  df-un 3912  df-in 3914  df-ss 3924  df-nul 4289  df-if 4484  df-sn 4586  df-pr 4588  df-op 4592  df-uni 4869  df-iun 4954  df-br 5106  df-opab 5168  df-id 5547  df-xp 5658  df-rel 5659  df-cnv 5660  df-co 5661  df-fun 6527
This theorem is referenced by:  funcnvuni  7917  fun11uni  7918  fiun  7928  axdc3lem2  10423
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