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Theorem nfafv 48206
Description: Bound-variable hypothesis builder for function value, analogous to nffv 6895. To prove a deduction version of this analogous to nffvd 6897 is not easily possible because a deduction version of nfdfat 48197 cannot be shown easily. (Contributed by Alexander van der Vekens, 26-May-2017.)
Hypotheses
Ref Expression
nfafv.1 Ⅎ𝑥𝐹
nfafv.2 Ⅎ𝑥𝐴
Assertion
Ref Expression
nfafv Ⅎ𝑥(𝐹'''𝐴)

Proof of Theorem nfafv
StepHypRef Expression
1 dfafv2 48202 . 2 (𝐹'''𝐴) = if(𝐹 defAt 𝐴, (𝐹‘𝐴), V)
2 nfafv.1 . . . 4 Ⅎ𝑥𝐹
3 nfafv.2 . . . 4 Ⅎ𝑥𝐴
42, 3nfdfat 48197 . . 3 Ⅎ𝑥 𝐹 defAt 𝐴
52, 3nffv 6895 . . 3 Ⅎ𝑥(𝐹‘𝐴)
6 nfcv 2922 . . 3 Ⅎ𝑥V
74, 5, 6nfif 4512 . 2 Ⅎ𝑥if(𝐹 defAt 𝐴, (𝐹‘𝐴), V)
81, 7nfcxfr 2920 1 Ⅎ𝑥(𝐹'''𝐴)
Colors of variables:    wff setvar class
This proof depends on syntax axioms:  Ⅎwnfc 2907  Vcvv 3450  ifcif 4481  ‘cfv 6538   defAt wdfat 48186  '''cafv 48187
This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1827  ax-4 1841  ax-5 1942  ax-6 1999  ax-7 2040  ax-8 2146  ax-9 2154  ax-10 2177  ax-11 2193  ax-12 2212  ax-ext 2732  ax-sep 5248  ax-nul 5259  ax-pr 5390
This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-3an 1105  df-tru 1572  df-fal 1582  df-ex 1812  df-nf 1816  df-sb 2099  df-mo 2564  df-eu 2594  df-clab 2739  df-cleq 2752  df-clel 2835  df-nfc 2909  df-ne 2956  df-ral 3077  df-rex 3087  df-rab 3413  df-v 3452  df-sbc 3739  df-csb 3847  df-ss 3896  df-dif 4047  df-in 4091  df-un 4151  df-nul 4279  df-if 4482  df-sn 4584  df-pr 4586  df-op 4590  df-uni 4867  df-int 4907  df-br 5103  df-opab 5167  df-id 5545  df-xp 5656  df-rel 5657  df-cnv 5658  df-co 5659  df-dm 5660  df-res 5662  df-iota 6494  df-fun 6540  df-fv 6546  df-aiota 48155  df-dfat 48189  df-afv 48190
This theorem is used by:  csbafv12g  48207  nfaov  48249
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