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Theorem dfatafv2eqfv 47273
Description: If a function is defined at a class 𝐴, the alternate function value equals the function's value at 𝐴. (Contributed by AV, 3-Sep-2022.)
Assertion
Ref Expression
dfatafv2eqfv (𝐹 defAt 𝐴 → (𝐹''''𝐴) = (𝐹𝐴))

Proof of Theorem dfatafv2eqfv
StepHypRef Expression
1 dfafv22 47271 . 2 (𝐹''''𝐴) = if(𝐹 defAt 𝐴, (𝐹𝐴), 𝒫 ran 𝐹)
2 iftrue 4531 . 2 (𝐹 defAt 𝐴 → if(𝐹 defAt 𝐴, (𝐹𝐴), 𝒫 ran 𝐹) = (𝐹𝐴))
31, 2eqtrid 2789 1 (𝐹 defAt 𝐴 → (𝐹''''𝐴) = (𝐹𝐴))
Colors of variables: wff setvar class
Syntax hints:  wi 4   = wceq 1540  ifcif 4525  𝒫 cpw 4600   cuni 4907  ran crn 5686  cfv 6561   defAt wdfat 47128  ''''cafv2 47220
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 2007  ax-8 2110  ax-9 2118  ax-ext 2708
This theorem depends on definitions:  df-bi 207  df-an 396  df-or 849  df-tru 1543  df-ex 1780  df-sb 2065  df-clab 2715  df-cleq 2729  df-clel 2816  df-rab 3437  df-v 3482  df-un 3956  df-if 4526  df-fv 6569  df-afv2 47221
This theorem is referenced by:  afv2rnfveq  47274  afv20fv0  47275  afv2fvn0fveq  47276
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