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Theorem unpreima 7082
Description: Preimage of a union. (Contributed by Jeff Madsen, 2-Sep-2009.)
Assertion
Ref Expression
unpreima (Fun 𝐹 → (𝐹 “ (𝐴𝐵)) = ((𝐹𝐴) ∪ (𝐹𝐵)))

Proof of Theorem unpreima
Dummy variable 𝑥 is distinct from all other variables.
StepHypRef Expression
1 funfn 6597 . 2 (Fun 𝐹𝐹 Fn dom 𝐹)
2 elpreima 7077 . . . 4 (𝐹 Fn dom 𝐹 → (𝑥 ∈ (𝐹 “ (𝐴𝐵)) ↔ (𝑥 ∈ dom 𝐹 ∧ (𝐹𝑥) ∈ (𝐴𝐵))))
3 elun 4162 . . . . . . 7 ((𝐹𝑥) ∈ (𝐴𝐵) ↔ ((𝐹𝑥) ∈ 𝐴 ∨ (𝐹𝑥) ∈ 𝐵))
43anbi2i 623 . . . . . 6 ((𝑥 ∈ dom 𝐹 ∧ (𝐹𝑥) ∈ (𝐴𝐵)) ↔ (𝑥 ∈ dom 𝐹 ∧ ((𝐹𝑥) ∈ 𝐴 ∨ (𝐹𝑥) ∈ 𝐵)))
5 andi 1009 . . . . . 6 ((𝑥 ∈ dom 𝐹 ∧ ((𝐹𝑥) ∈ 𝐴 ∨ (𝐹𝑥) ∈ 𝐵)) ↔ ((𝑥 ∈ dom 𝐹 ∧ (𝐹𝑥) ∈ 𝐴) ∨ (𝑥 ∈ dom 𝐹 ∧ (𝐹𝑥) ∈ 𝐵)))
64, 5bitri 275 . . . . 5 ((𝑥 ∈ dom 𝐹 ∧ (𝐹𝑥) ∈ (𝐴𝐵)) ↔ ((𝑥 ∈ dom 𝐹 ∧ (𝐹𝑥) ∈ 𝐴) ∨ (𝑥 ∈ dom 𝐹 ∧ (𝐹𝑥) ∈ 𝐵)))
7 elun 4162 . . . . . 6 (𝑥 ∈ ((𝐹𝐴) ∪ (𝐹𝐵)) ↔ (𝑥 ∈ (𝐹𝐴) ∨ 𝑥 ∈ (𝐹𝐵)))
8 elpreima 7077 . . . . . . 7 (𝐹 Fn dom 𝐹 → (𝑥 ∈ (𝐹𝐴) ↔ (𝑥 ∈ dom 𝐹 ∧ (𝐹𝑥) ∈ 𝐴)))
9 elpreima 7077 . . . . . . 7 (𝐹 Fn dom 𝐹 → (𝑥 ∈ (𝐹𝐵) ↔ (𝑥 ∈ dom 𝐹 ∧ (𝐹𝑥) ∈ 𝐵)))
108, 9orbi12d 918 . . . . . 6 (𝐹 Fn dom 𝐹 → ((𝑥 ∈ (𝐹𝐴) ∨ 𝑥 ∈ (𝐹𝐵)) ↔ ((𝑥 ∈ dom 𝐹 ∧ (𝐹𝑥) ∈ 𝐴) ∨ (𝑥 ∈ dom 𝐹 ∧ (𝐹𝑥) ∈ 𝐵))))
117, 10bitrid 283 . . . . 5 (𝐹 Fn dom 𝐹 → (𝑥 ∈ ((𝐹𝐴) ∪ (𝐹𝐵)) ↔ ((𝑥 ∈ dom 𝐹 ∧ (𝐹𝑥) ∈ 𝐴) ∨ (𝑥 ∈ dom 𝐹 ∧ (𝐹𝑥) ∈ 𝐵))))
126, 11bitr4id 290 . . . 4 (𝐹 Fn dom 𝐹 → ((𝑥 ∈ dom 𝐹 ∧ (𝐹𝑥) ∈ (𝐴𝐵)) ↔ 𝑥 ∈ ((𝐹𝐴) ∪ (𝐹𝐵))))
132, 12bitrd 279 . . 3 (𝐹 Fn dom 𝐹 → (𝑥 ∈ (𝐹 “ (𝐴𝐵)) ↔ 𝑥 ∈ ((𝐹𝐴) ∪ (𝐹𝐵))))
1413eqrdv 2732 . 2 (𝐹 Fn dom 𝐹 → (𝐹 “ (𝐴𝐵)) = ((𝐹𝐴) ∪ (𝐹𝐵)))
151, 14sylbi 217 1 (Fun 𝐹 → (𝐹 “ (𝐴𝐵)) = ((𝐹𝐴) ∪ (𝐹𝐵)))
Colors of variables: wff setvar class
Syntax hints:  wi 4  wa 395  wo 847   = wceq 1536  wcel 2105  cun 3960  ccnv 5687  dom cdm 5688  cima 5691  Fun wfun 6556   Fn wfn 6557  cfv 6562
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1791  ax-4 1805  ax-5 1907  ax-6 1964  ax-7 2004  ax-8 2107  ax-9 2115  ax-10 2138  ax-12 2174  ax-ext 2705  ax-sep 5301  ax-nul 5311  ax-pr 5437
This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3an 1088  df-tru 1539  df-fal 1549  df-ex 1776  df-nf 1780  df-sb 2062  df-mo 2537  df-eu 2566  df-clab 2712  df-cleq 2726  df-clel 2813  df-ne 2938  df-ral 3059  df-rex 3068  df-rab 3433  df-v 3479  df-dif 3965  df-un 3967  df-in 3969  df-ss 3979  df-nul 4339  df-if 4531  df-sn 4631  df-pr 4633  df-op 4637  df-uni 4912  df-br 5148  df-opab 5210  df-id 5582  df-xp 5694  df-rel 5695  df-cnv 5696  df-co 5697  df-dm 5698  df-rn 5699  df-res 5700  df-ima 5701  df-iota 6515  df-fun 6564  df-fn 6565  df-fv 6570
This theorem is referenced by:  sibfof  34321
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