Theorem or42 85

Description: Rearrange disjuncts.

Assertion

Ref	Expression
or42	((a v b) v (c v d)) = ((a v d) v (b v c))

Proof of Theorem or42

Step	Hyp	Ref	Expression
1		ax-a2 31	. . 3 (c v d) = (d v c)
2	1	lor 70	. 2 ((a v b) v (c v d)) = ((a v b) v (d v c))
3		or4 84	. 2 ((a v b) v (d v c)) = ((a v d) v (b v c))
4	2, 3	ax-r2 36	1 ((a v b) v (c v d)) = ((a v d) v (b v c))

Syntax hints:   = wb 1   v wo 6

This theorem is referenced by:  wdcom 1102

This theorem was proved from axioms:  ax-a2 31  ax-a3 32  ax-r1 35  ax-r2 36  ax-r5 38

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