ONE\_OF _ _ _ _ _ _ _ _ _ _ _ _ type
The operator one_of is used to represent an indefinite choice of one element from a finite set of objects.
x=one_of{1,2,5}
this equation encodes that x can take one of the values 1,2 or 5
REDUCE generates a one_of form in cases when an implicit root_of expression could be converted to an explicit solution set. A one_of form can be converted to a solve solution using expand_cases. See root_of.