



 
Hi, A partition of a set is a collection of nonempty subsets of the set such that every element of the set is in at least one of the subsets and no element of the set is in more than one of the subsets. You have written partitions of the set $A$ as sets which is certainly valid. {{a},{b,c}} is a partition of $A$ as are {{a,b},{c}}, {{a,c},{b}}, {{a},{b},{c}} and {{a,b,c}}. There are exactly 5 partitions of a set with 3 elements. Harley 



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