Theorem or4 528

Description: Rearrangement of 4 disjuncts. (Contributed by NM, 12-Aug-1994.)

Assertion

Ref	Expression
or4

Proof of Theorem or4

Step	Hyp	Ref	Expression
1		or12 523	. . 3
2	1	orbi2i 519	. 2
3		orass 524	. 2
4		orass 524	. 2
5	2, 3, 4	3bitr4i 277	1

Syntax hints:  <->wb 184  \/wo 368

This theorem is referenced by:  or42  529  orordi  530  orordir  531  3or6  1310  swoer  7358  xmullem2  11486

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 185  df-or 370