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Theorem 3orbi123i 1195
 Description: Join 3 biconditionals with disjunction. (Contributed by NM, 17-May-1994.)
Hypotheses
Ref Expression
bi3.1
bi3.2
bi3.3
Assertion
Ref Expression
3orbi123i

Proof of Theorem 3orbi123i
StepHypRef Expression
1 bi3.1 . . . 4
2 bi3.2 . . . 4
31, 2orbi12i 523 . . 3
4 bi3.3 . . 3
53, 4orbi12i 523 . 2
6 df-3or 983 . 2
7 df-3or 983 . 2
85, 6, 73bitr4i 280 1
 Colors of variables: wff setvar class Syntax hints:   wb 187   wo 369   w3o 981 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8 This theorem depends on definitions:  df-bi 188  df-or 371  df-3or 983 This theorem is referenced by:  ne3anior  2757  wecmpep  4846  cnvso  5395  sorpss  6590  ordon  6623  soxp  6920  dford2  8125  axlowdimlem6  24823  elxrge02  28239  brtp  30176  socnv  30192  dfon2  30225  sltsolem1  30342  frege129d  35993
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