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Theorem idfu1 16363
 Description: Value of the object part of the identity functor. (Contributed by Mario Carneiro, 3-Jan-2017.)
Hypotheses
Ref Expression
idfuval.i 𝐼 = (idfunc𝐶)
idfuval.b 𝐵 = (Base‘𝐶)
idfuval.c (𝜑𝐶 ∈ Cat)
idfu1.x (𝜑𝑋𝐵)
Assertion
Ref Expression
idfu1 (𝜑 → ((1st𝐼)‘𝑋) = 𝑋)

Proof of Theorem idfu1
StepHypRef Expression
1 idfuval.i . . . 4 𝐼 = (idfunc𝐶)
2 idfuval.b . . . 4 𝐵 = (Base‘𝐶)
3 idfuval.c . . . 4 (𝜑𝐶 ∈ Cat)
41, 2, 3idfu1st 16362 . . 3 (𝜑 → (1st𝐼) = ( I ↾ 𝐵))
54fveq1d 6105 . 2 (𝜑 → ((1st𝐼)‘𝑋) = (( I ↾ 𝐵)‘𝑋))
6 idfu1.x . . 3 (𝜑𝑋𝐵)
7 fvresi 6344 . . 3 (𝑋𝐵 → (( I ↾ 𝐵)‘𝑋) = 𝑋)
86, 7syl 17 . 2 (𝜑 → (( I ↾ 𝐵)‘𝑋) = 𝑋)
95, 8eqtrd 2644 1 (𝜑 → ((1st𝐼)‘𝑋) = 𝑋)
 Colors of variables: wff setvar class Syntax hints:   → wi 4   = wceq 1475   ∈ wcel 1977   I cid 4948   ↾ cres 5040  ‘cfv 5804  1st c1st 7057  Basecbs 15695  Catccat 16148  idfunccidfu 16338 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1713  ax-4 1728  ax-5 1827  ax-6 1875  ax-7 1922  ax-8 1979  ax-9 1986  ax-10 2006  ax-11 2021  ax-12 2034  ax-13 2234  ax-ext 2590  ax-rep 4699  ax-sep 4709  ax-nul 4717  ax-pow 4769  ax-pr 4833  ax-un 6847 This theorem depends on definitions:  df-bi 196  df-or 384  df-an 385  df-3an 1033  df-tru 1478  df-ex 1696  df-nf 1701  df-sb 1868  df-eu 2462  df-mo 2463  df-clab 2597  df-cleq 2603  df-clel 2606  df-nfc 2740  df-ne 2782  df-ral 2901  df-rex 2902  df-reu 2903  df-rab 2905  df-v 3175  df-sbc 3403  df-csb 3500  df-dif 3543  df-un 3545  df-in 3547  df-ss 3554  df-nul 3875  df-if 4037  df-pw 4110  df-sn 4126  df-pr 4128  df-op 4132  df-uni 4373  df-iun 4457  df-br 4584  df-opab 4644  df-mpt 4645  df-id 4953  df-xp 5044  df-rel 5045  df-cnv 5046  df-co 5047  df-dm 5048  df-rn 5049  df-res 5050  df-ima 5051  df-iota 5768  df-fun 5806  df-fn 5807  df-f 5808  df-f1 5809  df-fo 5810  df-f1o 5811  df-fv 5812  df-1st 7059  df-idfu 16342 This theorem is referenced by:  idffth  16416  ressffth  16421  catciso  16580
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