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Theorem rb-ax1 1517
Description: The first of four axioms in the Russell-Bernays axiom system. (Contributed by Anthony Hart, 13-Aug-2011.) (Proof modification is discouraged.) (New usage is discouraged.)
Assertion
Ref Expression
rb-ax1

Proof of Theorem rb-ax1
StepHypRef Expression
1 orim2 814 . . 3
2 imor 401 . . 3
3 imor 401 . . 3
41, 2, 33imtr3i 256 . 2
54imori 402 1
Colors of variables: wff setvar class
Syntax hints:   wn 3   wi 4   wo 357
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 177  df-or 359  df-an 360
This theorem is referenced by:  rbsyl  1521  rblem1  1522  rblem2  1523  rblem4  1525  re2luk1  1530
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