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Theorem fneq2 6624
Description: Equality theorem for function predicate with domain. (Contributed by NM, 1-Aug-1994.)
Assertion
Ref Expression
fneq2 (𝐴 = 𝐵 → (𝐹 Fn 𝐴𝐹 Fn 𝐵))

Proof of Theorem fneq2
StepHypRef Expression
1 eqeq2 2772 . . 3 (𝐴 = 𝐵 → (dom 𝐹 = 𝐴 ↔ dom 𝐹 = 𝐵))
21anbi2d 642 . 2 (𝐴 = 𝐵 → ((Fun 𝐹 ∧ dom 𝐹 = 𝐴) ↔ (Fun 𝐹 ∧ dom 𝐹 = 𝐵)))
3 df-fn 6536 . 2 (𝐹 Fn 𝐴 ↔ (Fun 𝐹 ∧ dom 𝐹 = 𝐴))
4 df-fn 6536 . 2 (𝐹 Fn 𝐵 ↔ (Fun 𝐹 ∧ dom 𝐹 = 𝐵))
52, 3, 43bitr4g 317 1 (𝐴 = 𝐵 → (𝐹 Fn 𝐴𝐹 Fn 𝐵))
Colors of variables:    wff setvar class
This proof depends on syntax axioms:  wi 4  wb 209  wa 401   = wceq 1570  dom cdm 5655  Fun wfun 6527   Fn wfn 6528
This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-9 2155  ax-ext 2732
This proof depends on definitions:  df-bi 210  df-an 402  df-ex 1813  df-cleq 2752  df-fn 6536
This theorem is used by:  fneq2d  6626  fneq2i  6630  feq2  6681  foeq2  6786  f1o00  6853  eqfnfv2  7023  frrlem1  8285  frrlem13  8297  tfrlem12  8378  ixpeq1  8915  ac5  10479  0fz1  13598  fconst7v  33093  esumcvgsum  34598  bnj90  35232  bnj919  35277  bnj535  35399  bnj1463  35564  fnchoice  45863
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