1.8.8 Advanced Topic: Lists as SetsMathematica usually keeps the elements of a list in exactly the order you originally entered them. If you want to treat a Mathematica list like a mathematical set, however, you may want to ignore the order of elements in the list.
Union[ ,  , ... ] | give a list of the distinct elements in the  | Intersection[ ,  , ... ] | give a list of the elements that are common to all the  | Complement[universal,  , ... ] | give a list of the elements that are in universal, but not in any of the  | | Subsets[list] | give a list of all subsets of the elements in list |
Set theoretical functions. | Union gives the elements that occur in any of the lists. | |
In[1]:=
Union[{c, a, b}, {d, a, c}, {a, e}]
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| Intersection gives only elements that occur in all the lists. | |
In[2]:=
Intersection[{a, c, b}, {b, a, d, a}]
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| Complement gives elements that occur in the first list, but not in any of the others. | |
In[3]:=
Complement[{a, b, c, d}, {a, d}]
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| This gives all the subsets of the list. | |
In[4]:=
Subsets[{a, b, c}]
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