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Theorem bj-fununsn1 36788
Description: Value of a function expressed as a union of a function and a singleton on a couple (with disjoint domain) at a point not equal to the first component of that couple. (Contributed by BJ, 18-Mar-2023.) (Proof modification is discouraged.)
Hypotheses
Ref Expression
bj-fununsn.un (𝜑𝐹 = (𝐺 ∪ {⟨𝐵, 𝐶⟩}))
bj-fununsn1.neq (𝜑 → ¬ 𝐴 = 𝐵)
Assertion
Ref Expression
bj-fununsn1 (𝜑 → (𝐹𝐴) = (𝐺𝐴))

Proof of Theorem bj-fununsn1
StepHypRef Expression
1 bj-fununsn.un . 2 (𝜑𝐹 = (𝐺 ∪ {⟨𝐵, 𝐶⟩}))
2 dmsnopss 6213 . . . 4 dom {⟨𝐵, 𝐶⟩} ⊆ {𝐵}
32a1i 11 . . 3 (𝜑 → dom {⟨𝐵, 𝐶⟩} ⊆ {𝐵})
4 bj-fununsn1.neq . . . 4 (𝜑 → ¬ 𝐴 = 𝐵)
5 elsni 4641 . . . 4 (𝐴 ∈ {𝐵} → 𝐴 = 𝐵)
64, 5nsyl 140 . . 3 (𝜑 → ¬ 𝐴 ∈ {𝐵})
73, 6ssneldd 3975 . 2 (𝜑 → ¬ 𝐴 ∈ dom {⟨𝐵, 𝐶⟩})
81, 7bj-funun 36787 1 (𝜑 → (𝐹𝐴) = (𝐺𝐴))
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4   = wceq 1533  wcel 2098  cun 3938  wss 3940  {csn 4624  cop 4630  dom cdm 5672  cfv 6542
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1789  ax-4 1803  ax-5 1905  ax-6 1963  ax-7 2003  ax-8 2100  ax-9 2108  ax-10 2129  ax-11 2146  ax-12 2166  ax-ext 2696  ax-sep 5294  ax-nul 5301  ax-pr 5423
This theorem depends on definitions:  df-bi 206  df-an 395  df-or 846  df-3an 1086  df-tru 1536  df-fal 1546  df-ex 1774  df-nf 1778  df-sb 2060  df-mo 2528  df-eu 2557  df-clab 2703  df-cleq 2717  df-clel 2802  df-ne 2931  df-ral 3052  df-rex 3061  df-rab 3420  df-v 3465  df-dif 3943  df-un 3945  df-in 3947  df-ss 3957  df-nul 4319  df-if 4525  df-sn 4625  df-pr 4627  df-op 4631  df-uni 4904  df-br 5144  df-opab 5206  df-xp 5678  df-cnv 5680  df-dm 5682  df-rn 5683  df-res 5684  df-ima 5685  df-iota 6494  df-fv 6550
This theorem is referenced by:  bj-fvsnun1  36790  bj-fvmptunsn2  36793
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