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Theorem ot1stg 5721
Description: Extract the first member of an ordered triple. (Due to infrequent usage, it isn't worthwhile at this point to define special extractors for triples, so we reuse the ordered pair extractors for ot1stg 5721, ot2ndg 5722, ot3rdgg 5723.) (Contributed by NM, 3-Apr-2015.) (Revised by Mario Carneiro, 2-May-2015.)
Assertion
Ref Expression
ot1stg ((A 𝑉 B 𝑊 𝐶 𝑋) → (1st ‘(1st ‘⟨A, B, 𝐶⟩)) = A)

Proof of Theorem ot1stg
StepHypRef Expression
1 df-ot 3377 . . . . 5 A, B, 𝐶⟩ = ⟨⟨A, B⟩, 𝐶
21fveq2i 5124 . . . 4 (1st ‘⟨A, B, 𝐶⟩) = (1st ‘⟨⟨A, B⟩, 𝐶⟩)
3 opexg 3955 . . . . . 6 ((A 𝑉 B 𝑊) → ⟨A, B V)
4 op1stg 5719 . . . . . 6 ((⟨A, B V 𝐶 𝑋) → (1st ‘⟨⟨A, B⟩, 𝐶⟩) = ⟨A, B⟩)
53, 4sylan 267 . . . . 5 (((A 𝑉 B 𝑊) 𝐶 𝑋) → (1st ‘⟨⟨A, B⟩, 𝐶⟩) = ⟨A, B⟩)
653impa 1098 . . . 4 ((A 𝑉 B 𝑊 𝐶 𝑋) → (1st ‘⟨⟨A, B⟩, 𝐶⟩) = ⟨A, B⟩)
72, 6syl5eq 2081 . . 3 ((A 𝑉 B 𝑊 𝐶 𝑋) → (1st ‘⟨A, B, 𝐶⟩) = ⟨A, B⟩)
87fveq2d 5125 . 2 ((A 𝑉 B 𝑊 𝐶 𝑋) → (1st ‘(1st ‘⟨A, B, 𝐶⟩)) = (1st ‘⟨A, B⟩))
9 op1stg 5719 . . 3 ((A 𝑉 B 𝑊) → (1st ‘⟨A, B⟩) = A)
1093adant3 923 . 2 ((A 𝑉 B 𝑊 𝐶 𝑋) → (1st ‘⟨A, B⟩) = A)
118, 10eqtrd 2069 1 ((A 𝑉 B 𝑊 𝐶 𝑋) → (1st ‘(1st ‘⟨A, B, 𝐶⟩)) = A)
Colors of variables: wff set class
Syntax hints:  wi 4   wa 97   w3a 884   = wceq 1242   wcel 1390  Vcvv 2551  cop 3370  cotp 3371  cfv 4845  1st c1st 5707
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-io 629  ax-5 1333  ax-7 1334  ax-gen 1335  ax-ie1 1379  ax-ie2 1380  ax-8 1392  ax-10 1393  ax-11 1394  ax-i12 1395  ax-bnd 1396  ax-4 1397  ax-13 1401  ax-14 1402  ax-17 1416  ax-i9 1420  ax-ial 1424  ax-i5r 1425  ax-ext 2019  ax-sep 3866  ax-pow 3918  ax-pr 3935  ax-un 4136
This theorem depends on definitions:  df-bi 110  df-3an 886  df-tru 1245  df-nf 1347  df-sb 1643  df-eu 1900  df-mo 1901  df-clab 2024  df-cleq 2030  df-clel 2033  df-nfc 2164  df-ral 2305  df-rex 2306  df-v 2553  df-sbc 2759  df-un 2916  df-in 2918  df-ss 2925  df-pw 3353  df-sn 3373  df-pr 3374  df-op 3376  df-ot 3377  df-uni 3572  df-br 3756  df-opab 3810  df-mpt 3811  df-id 4021  df-xp 4294  df-rel 4295  df-cnv 4296  df-co 4297  df-dm 4298  df-rn 4299  df-iota 4810  df-fun 4847  df-fv 4853  df-1st 5709
This theorem is referenced by: (None)
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