Theorem fvco2 6987

Description: Value of a function composition. Similar to second part of Theorem 3H of [Enderton] p. 47. (Contributed by NM, 9-Oct-2004.) (Proof shortened by Andrew Salmon, 22-Oct-2011.) (Revised by Stefan O'Rear, 16-Oct-2014.)

Assertion

Ref	Expression
fvco2	⊢ ((𝐺 Fn 𝐴 ∧ 𝑋 ∈ 𝐴) → ((𝐹 ∘ 𝐺)‘𝑋) = (𝐹‘(𝐺‘𝑋)))

Proof of Theorem fvco2

Dummy variable 𝑥 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		imaco 6253	. . . . 5 ⊢ ((𝐹 ∘ 𝐺) “ {𝑋}) = (𝐹 “ (𝐺 “ {𝑋}))
2		fnsnfv 6969	. . . . . 6 ⊢ ((𝐺 Fn 𝐴 ∧ 𝑋 ∈ 𝐴) → {(𝐺‘𝑋)} = (𝐺 “ {𝑋}))
3	2	imaeq2d 6060	. . . . 5 ⊢ ((𝐺 Fn 𝐴 ∧ 𝑋 ∈ 𝐴) → (𝐹 “ {(𝐺‘𝑋)}) = (𝐹 “ (𝐺 “ {𝑋})))
4	1, 3	eqtr4id 2788	. . . 4 ⊢ ((𝐺 Fn 𝐴 ∧ 𝑋 ∈ 𝐴) → ((𝐹 ∘ 𝐺) “ {𝑋}) = (𝐹 “ {(𝐺‘𝑋)}))
5	4	eleq2d 2819	. . 3 ⊢ ((𝐺 Fn 𝐴 ∧ 𝑋 ∈ 𝐴) → (𝑥 ∈ ((𝐹 ∘ 𝐺) “ {𝑋}) ↔ 𝑥 ∈ (𝐹 “ {(𝐺‘𝑋)})))
6	5	iotabidv 6526	. 2 ⊢ ((𝐺 Fn 𝐴 ∧ 𝑋 ∈ 𝐴) → (℩𝑥𝑥 ∈ ((𝐹 ∘ 𝐺) “ {𝑋})) = (℩𝑥𝑥 ∈ (𝐹 “ {(𝐺‘𝑋)})))
7		dffv3 6883	. 2 ⊢ ((𝐹 ∘ 𝐺)‘𝑋) = (℩𝑥𝑥 ∈ ((𝐹 ∘ 𝐺) “ {𝑋}))
8		dffv3 6883	. 2 ⊢ (𝐹‘(𝐺‘𝑋)) = (℩𝑥𝑥 ∈ (𝐹 “ {(𝐺‘𝑋)}))
9	6, 7, 8	3eqtr4g 2794	1 ⊢ ((𝐺 Fn 𝐴 ∧ 𝑋 ∈ 𝐴) → ((𝐹 ∘ 𝐺)‘𝑋) = (𝐹‘(𝐺‘𝑋)))

Syntax hints:   → wi 4   ∧ wa 395   = wceq 1539   ∈ wcel 2107  {csn 4608   “ cima 5670   ∘ ccom 5671  ℩cio 6493   Fn wfn 6537  ‘cfv 6542

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1794  ax-4 1808  ax-5 1909  ax-6 1966  ax-7 2006  ax-8 2109  ax-9 2117  ax-10 2140  ax-11 2156  ax-12 2176  ax-ext 2706  ax-sep 5278  ax-nul 5288  ax-pr 5414

This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3an 1088  df-tru 1542  df-fal 1552  df-ex 1779  df-nf 1783  df-sb 2064  df-mo 2538  df-eu 2567  df-clab 2713  df-cleq 2726  df-clel 2808  df-ne 2932  df-ral 3051  df-rex 3060  df-rab 3421  df-v 3466  df-dif 3936  df-un 3938  df-in 3940  df-ss 3950  df-nul 4316  df-if 4508  df-sn 4609  df-pr 4611  df-op 4615  df-uni 4890  df-br 5126  df-opab 5188  df-id 5560  df-xp 5673  df-rel 5674  df-cnv 5675  df-co 5676  df-dm 5677  df-rn 5678  df-res 5679  df-ima 5680  df-iota 6495  df-fun 6544  df-fn 6545  df-fv 6550

This theorem is referenced by:  fvco  6988  fvco3  6989  fvco4i  6991  fvcofneq  7094  coof  7704  ofco  7705  curry1  8112  curry2  8115  fsplitfpar  8126  enfixsn  9104  updjudhcoinlf  9955  updjudhcoinrg  9956  updjud  9957  smobeth  10609  fpwwe  10669  addpqnq  10961  mulpqnq  10964  revco  14856  ccatco  14857  cshco  14858  swrdco  14859  isoval  17785  prdsidlem  18756  gsumwmhm  18832  prdsinvlem  19041  ghmquskerco  19276  gsmsymgrfixlem1  19418  f1omvdconj  19437  pmtrfinv  19452  symggen  19461  symgtrinv  19463  pmtr3ncomlem1  19464  prdsmgp  20121  ringidval  20153  lmhmco  21015  chrrhm  21513  cofipsgn  21578  dsmmbas2  21724  dsmm0cl  21727  frlmbas  21742  frlmup3  21787  frlmup4  21788  f1lindf  21809  lindfmm  21814  evlslem1  22073  evlsvar  22081  m1detdiag  22570  1stccnp  23435  prdstopn  23601  xpstopnlem2  23784  uniioombllem6  25578  precsexlem1  28186  precsexlem2  28187  precsexlem3  28188  precsexlem4  28189  precsexlem5  28190  ex-fpar  30428  0vfval  30572  cnre2csqlem  33850  mblfinlem2  37606  rabren3dioph  42771  hausgraph  43162  stoweidlem59  46019  afvco2  47134  gricushgr  47832  ackvalsucsucval  48555