or4 - Intuitionistic Logic Explorer

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Theorem or4 720

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 715	. . 3 $\/$ $\/$ $\/$ $\/$
2	1	orbi2i 711	. 2 $\/$ $\/$ $\/$ $\/$ $\/$ $\/$
3		orass 716	. 2 $\/$ $\/$ $\/$ $\/$ $\/$ $\/$
4		orass 716	. 2 $\/$ $\/$ $\/$ $\/$ $\/$ $\/$
5	2, 3, 4	3bitr4i 210	1 $\/$ $\/$ $\/$ $\/$ $\/$ $\/$

Colors of variables: wff set class

Syntax hints:

wb 103 $\/$ wo 661

This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 104 ax-ia2 105 ax-ia3 106 ax-io 662

This theorem depends on definitions: df-bi 115

This theorem is referenced by: or42 721 orordi 722 orordir 723 3or6 1254 swoer 6157 apcotr 7707