subsets {...} -- produce all the subsets

subsets {...} -- produce all the subsets

Synopsis:

Function: subsets -- produce all the subsets

Input:

an instance of class List.

subsets s -- yields a list of the subsets of the list s.

The subsets are returned as lists whose elements are in the same order.

i1 : subsets {1,2,3}



o1 = {{}, {1}, {2}, {1, 2}, {3}, {1, 3}, {2, 3}, {1, 2, 3}}



o1 : List

See also:

subsets -- produce all the subsets

Code:

     -- ../../../Macaulay2/m2/combinatorics.m2:19-25
     subsets List := x -> (
          if #x === 0 then {x}
          else (
               a := x#-1;
               x = drop(x,-1);
               s := subsets x;
               join(s,apply(s,y->append(y,a)))))