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Theorem or4 688

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 683	. . 3 $\/$ $\/$ $\/$ $\/$
2	1	orbi2i 679	. 2 $\/$ $\/$ $\/$ $\/$ $\/$ $\/$
3		orass 684	. 2 $\/$ $\/$ $\/$ $\/$ $\/$ $\/$
4		orass 684	. 2 $\/$ $\/$ $\/$ $\/$ $\/$ $\/$
5	2, 3, 4	3bitr4i 201	1 $\/$ $\/$ $\/$ $\/$ $\/$ $\/$

Colors of variables: wff set class

Syntax hints:

wb 98 $\/$ wo 629

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 630

This theorem depends on definitions: df-bi 110

This theorem is referenced by: or42 689 orordi 690 orordir 691 3or6 1218 swoer 6134 apcotr 7598