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Theorem djufun 6763
Description: The "domain-disjoint-union" of two functions is a function. (Contributed by BJ, 10-Jul-2022.)
Hypotheses
Ref Expression
djufun.f (𝜑 → Fun 𝐹)
djufun.g (𝜑 → Fun 𝐺)
Assertion
Ref Expression
djufun (𝜑 → Fun (𝐹d 𝐺))

Proof of Theorem djufun
StepHypRef Expression
1 djufun.f . . . 4 (𝜑 → Fun 𝐹)
2 inlresf1 6732 . . . . 5 (inl ↾ dom 𝐹):dom 𝐹1-1→(dom 𝐹 ⊔ dom 𝐺)
3 df-f1 5007 . . . . . 6 ((inl ↾ dom 𝐹):dom 𝐹1-1→(dom 𝐹 ⊔ dom 𝐺) ↔ ((inl ↾ dom 𝐹):dom 𝐹⟶(dom 𝐹 ⊔ dom 𝐺) ∧ Fun (inl ↾ dom 𝐹)))
43simprbi 269 . . . . 5 ((inl ↾ dom 𝐹):dom 𝐹1-1→(dom 𝐹 ⊔ dom 𝐺) → Fun (inl ↾ dom 𝐹))
52, 4mp1i 10 . . . 4 (𝜑 → Fun (inl ↾ dom 𝐹))
6 funco 5040 . . . 4 ((Fun 𝐹 ∧ Fun (inl ↾ dom 𝐹)) → Fun (𝐹(inl ↾ dom 𝐹)))
71, 5, 6syl2anc 403 . . 3 (𝜑 → Fun (𝐹(inl ↾ dom 𝐹)))
8 djufun.g . . . 4 (𝜑 → Fun 𝐺)
9 inrresf1 6733 . . . . 5 (inr ↾ dom 𝐺):dom 𝐺1-1→(dom 𝐹 ⊔ dom 𝐺)
10 df-f1 5007 . . . . . 6 ((inr ↾ dom 𝐺):dom 𝐺1-1→(dom 𝐹 ⊔ dom 𝐺) ↔ ((inr ↾ dom 𝐺):dom 𝐺⟶(dom 𝐹 ⊔ dom 𝐺) ∧ Fun (inr ↾ dom 𝐺)))
1110simprbi 269 . . . . 5 ((inr ↾ dom 𝐺):dom 𝐺1-1→(dom 𝐹 ⊔ dom 𝐺) → Fun (inr ↾ dom 𝐺))
129, 11mp1i 10 . . . 4 (𝜑 → Fun (inr ↾ dom 𝐺))
13 funco 5040 . . . 4 ((Fun 𝐺 ∧ Fun (inr ↾ dom 𝐺)) → Fun (𝐺(inr ↾ dom 𝐺)))
148, 12, 13syl2anc 403 . . 3 (𝜑 → Fun (𝐺(inr ↾ dom 𝐺)))
15 dmcoss 4690 . . . . . . 7 dom (𝐹(inl ↾ dom 𝐹)) ⊆ dom (inl ↾ dom 𝐹)
16 df-rn 4439 . . . . . . 7 ran (inl ↾ dom 𝐹) = dom (inl ↾ dom 𝐹)
1715, 16sseqtr4i 3057 . . . . . 6 dom (𝐹(inl ↾ dom 𝐹)) ⊆ ran (inl ↾ dom 𝐹)
18 dmcoss 4690 . . . . . . 7 dom (𝐺(inr ↾ dom 𝐺)) ⊆ dom (inr ↾ dom 𝐺)
19 df-rn 4439 . . . . . . 7 ran (inr ↾ dom 𝐺) = dom (inr ↾ dom 𝐺)
2018, 19sseqtr4i 3057 . . . . . 6 dom (𝐺(inr ↾ dom 𝐺)) ⊆ ran (inr ↾ dom 𝐺)
21 ss2in 3225 . . . . . 6 ((dom (𝐹(inl ↾ dom 𝐹)) ⊆ ran (inl ↾ dom 𝐹) ∧ dom (𝐺(inr ↾ dom 𝐺)) ⊆ ran (inr ↾ dom 𝐺)) → (dom (𝐹(inl ↾ dom 𝐹)) ∩ dom (𝐺(inr ↾ dom 𝐺))) ⊆ (ran (inl ↾ dom 𝐹) ∩ ran (inr ↾ dom 𝐺)))
2217, 20, 21mp2an 417 . . . . 5 (dom (𝐹(inl ↾ dom 𝐹)) ∩ dom (𝐺(inr ↾ dom 𝐺))) ⊆ (ran (inl ↾ dom 𝐹) ∩ ran (inr ↾ dom 𝐺))
23 djuinr 6734 . . . . . 6 (ran (inl ↾ dom 𝐹) ∩ ran (inr ↾ dom 𝐺)) = ∅
2423a1i 9 . . . . 5 (𝜑 → (ran (inl ↾ dom 𝐹) ∩ ran (inr ↾ dom 𝐺)) = ∅)
2522, 24syl5sseq 3072 . . . 4 (𝜑 → (dom (𝐹(inl ↾ dom 𝐹)) ∩ dom (𝐺(inr ↾ dom 𝐺))) ⊆ ∅)
26 ss0 3320 . . . 4 ((dom (𝐹(inl ↾ dom 𝐹)) ∩ dom (𝐺(inr ↾ dom 𝐺))) ⊆ ∅ → (dom (𝐹(inl ↾ dom 𝐹)) ∩ dom (𝐺(inr ↾ dom 𝐺))) = ∅)
2725, 26syl 14 . . 3 (𝜑 → (dom (𝐹(inl ↾ dom 𝐹)) ∩ dom (𝐺(inr ↾ dom 𝐺))) = ∅)
28 funun 5044 . . 3 (((Fun (𝐹(inl ↾ dom 𝐹)) ∧ Fun (𝐺(inr ↾ dom 𝐺))) ∧ (dom (𝐹(inl ↾ dom 𝐹)) ∩ dom (𝐺(inr ↾ dom 𝐺))) = ∅) → Fun ((𝐹(inl ↾ dom 𝐹)) ∪ (𝐺(inr ↾ dom 𝐺))))
297, 14, 27, 28syl21anc 1173 . 2 (𝜑 → Fun ((𝐹(inl ↾ dom 𝐹)) ∪ (𝐺(inr ↾ dom 𝐺))))
30 df-djud 6762 . . 3 (𝐹d 𝐺) = ((𝐹(inl ↾ dom 𝐹)) ∪ (𝐺(inr ↾ dom 𝐺)))
3130funeqi 5022 . 2 (Fun (𝐹d 𝐺) ↔ Fun ((𝐹(inl ↾ dom 𝐹)) ∪ (𝐺(inr ↾ dom 𝐺))))
3229, 31sylibr 132 1 (𝜑 → Fun (𝐹d 𝐺))
Colors of variables: wff set class
Syntax hints:  wi 4   = wceq 1289  cun 2995  cin 2996  wss 2997  c0 3284  ccnv 4427  dom cdm 4428  ran crn 4429  cres 4430  ccom 4432  Fun wfun 4996  wf 4998  1-1wf1 4999  cdju 6709  inlcinl 6716  inrcinr 6717  d cdjud 6761
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-in1 579  ax-in2 580  ax-io 665  ax-5 1381  ax-7 1382  ax-gen 1383  ax-ie1 1427  ax-ie2 1428  ax-8 1440  ax-10 1441  ax-11 1442  ax-i12 1443  ax-bndl 1444  ax-4 1445  ax-13 1449  ax-14 1450  ax-17 1464  ax-i9 1468  ax-ial 1472  ax-i5r 1473  ax-ext 2070  ax-sep 3949  ax-nul 3957  ax-pow 4001  ax-pr 4027  ax-un 4251
This theorem depends on definitions:  df-bi 115  df-3an 926  df-tru 1292  df-fal 1295  df-nf 1395  df-sb 1693  df-eu 1951  df-mo 1952  df-clab 2075  df-cleq 2081  df-clel 2084  df-nfc 2217  df-ne 2256  df-ral 2364  df-rex 2365  df-v 2621  df-sbc 2839  df-dif 2999  df-un 3001  df-in 3003  df-ss 3010  df-nul 3285  df-pw 3427  df-sn 3447  df-pr 3448  df-op 3450  df-uni 3649  df-br 3838  df-opab 3892  df-mpt 3893  df-tr 3929  df-id 4111  df-iord 4184  df-on 4186  df-suc 4189  df-xp 4434  df-rel 4435  df-cnv 4436  df-co 4437  df-dm 4438  df-rn 4439  df-res 4440  df-iota 4967  df-fun 5004  df-fn 5005  df-f 5006  df-f1 5007  df-fo 5008  df-f1o 5009  df-fv 5010  df-1st 5893  df-2nd 5894  df-1o 6163  df-dju 6710  df-inl 6718  df-inr 6719  df-djud 6762
This theorem is referenced by: (None)
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