There is a little confusion of terms going on here. Mathematically a set is an un-ordered collection. However, the powerset() routine in Data::PowerSet returns arrays which are ordered.

What powerset() is really doing is producing all the sub-sequences (with gaps between elements allowed) of the input sequence. If your input sequence contains distinct elements, then you can think of it as being a set and think of all of the generated sub-sequences as subsets. That is, there is a correspondence between a sequence of distinct elements and the set consisting of those elements.

So, the powerset() routine can be used to produce either 1) all the sub-sequences of a given sequence or 2) all the subsets of a given set.

In reply to Re^2: Subsets and adjacent values by pc88mxer
in thread Subsets and adjacent values by andreas1234567

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