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Theorem feq123d 5065
 Description: Equality deduction for functions. (Contributed by Paul Chapman, 22-Jun-2011.)
Hypotheses
Ref Expression
feq12d.1 (𝜑𝐹 = 𝐺)
feq12d.2 (𝜑𝐴 = 𝐵)
feq123d.3 (𝜑𝐶 = 𝐷)
Assertion
Ref Expression
feq123d (𝜑 → (𝐹:𝐴𝐶𝐺:𝐵𝐷))

Proof of Theorem feq123d
StepHypRef Expression
1 feq12d.1 . . 3 (𝜑𝐹 = 𝐺)
2 feq12d.2 . . 3 (𝜑𝐴 = 𝐵)
31, 2feq12d 5064 . 2 (𝜑 → (𝐹:𝐴𝐶𝐺:𝐵𝐶))
4 feq123d.3 . . 3 (𝜑𝐶 = 𝐷)
5 feq3 5060 . . 3 (𝐶 = 𝐷 → (𝐺:𝐵𝐶𝐺:𝐵𝐷))
64, 5syl 14 . 2 (𝜑 → (𝐺:𝐵𝐶𝐺:𝐵𝐷))
73, 6bitrd 181 1 (𝜑 → (𝐹:𝐴𝐶𝐺:𝐵𝐷))
 Colors of variables: wff set class Syntax hints:   → wi 4   ↔ wb 102   = wceq 1259  ⟶wf 4926 This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 103  ax-ia2 104  ax-ia3 105  ax-io 640  ax-5 1352  ax-7 1353  ax-gen 1354  ax-ie1 1398  ax-ie2 1399  ax-8 1411  ax-10 1412  ax-11 1413  ax-i12 1414  ax-bndl 1415  ax-4 1416  ax-17 1435  ax-i9 1439  ax-ial 1443  ax-i5r 1444  ax-ext 2038 This theorem depends on definitions:  df-bi 114  df-3an 898  df-tru 1262  df-nf 1366  df-sb 1662  df-clab 2043  df-cleq 2049  df-clel 2052  df-nfc 2183  df-v 2576  df-un 2950  df-in 2952  df-ss 2959  df-sn 3409  df-pr 3410  df-op 3412  df-br 3793  df-opab 3847  df-rel 4380  df-cnv 4381  df-co 4382  df-dm 4383  df-rn 4384  df-fun 4932  df-fn 4933  df-f 4934 This theorem is referenced by:  feq123  5066  feq23d  5070
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