Theorem bj-fununsn1 37248

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	⊢ (𝜑 → 𝐹 = (𝐺 ∪ {⟨𝐵, 𝐶⟩}))
bj-fununsn1.neq	⊢ (𝜑 → ¬ 𝐴 = 𝐵)

Assertion

Ref	Expression
bj-fununsn1	⊢ (𝜑 → (𝐹‘𝐴) = (𝐺‘𝐴))

Proof of Theorem bj-fununsn1

Step	Hyp	Ref	Expression
1		bj-fununsn.un	. 2 ⊢ (𝜑 → 𝐹 = (𝐺 ∪ {⟨𝐵, 𝐶⟩}))
2		dmsnopss 6190	. . . 4 ⊢ dom {⟨𝐵, 𝐶⟩} ⊆ {𝐵}
3	2	a1i 11	. . 3 ⊢ (𝜑 → dom {⟨𝐵, 𝐶⟩} ⊆ {𝐵})
4		bj-fununsn1.neq	. . . 4 ⊢ (𝜑 → ¬ 𝐴 = 𝐵)
5		elsni 4609	. . . 4 ⊢ (𝐴 ∈ {𝐵} → 𝐴 = 𝐵)
6	4, 5	nsyl 140	. . 3 ⊢ (𝜑 → ¬ 𝐴 ∈ {𝐵})
7	3, 6	ssneldd 3952	. 2 ⊢ (𝜑 → ¬ 𝐴 ∈ dom {⟨𝐵, 𝐶⟩})
8	1, 7	bj-funun 37247	1 ⊢ (𝜑 → (𝐹‘𝐴) = (𝐺‘𝐴))

Syntax hints:  ¬ wn 3   → wi 4   = wceq 1540   ∈ wcel 2109   ∪ cun 3915   ⊆ wss 3917  {csn 4592  ⟨cop 4598  dom cdm 5641  ‘cfv 6514

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1795  ax-4 1809  ax-5 1910  ax-6 1967  ax-7 2008  ax-8 2111  ax-9 2119  ax-10 2142  ax-11 2158  ax-12 2178  ax-ext 2702  ax-sep 5254  ax-nul 5264  ax-pr 5390

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3an 1088  df-tru 1543  df-fal 1553  df-ex 1780  df-nf 1784  df-sb 2066  df-mo 2534  df-eu 2563  df-clab 2709  df-cleq 2722  df-clel 2804  df-ne 2927  df-ral 3046  df-rex 3055  df-rab 3409  df-v 3452  df-dif 3920  df-un 3922  df-in 3924  df-ss 3934  df-nul 4300  df-if 4492  df-sn 4593  df-pr 4595  df-op 4599  df-uni 4875  df-br 5111  df-opab 5173  df-xp 5647  df-cnv 5649  df-dm 5651  df-rn 5652  df-res 5653  df-ima 5654  df-iota 6467  df-fv 6522

This theorem is referenced by:  bj-fvsnun1  37250  bj-fvmptunsn2  37253