The circuits of a matroid are the minimal dependent subsets of the ground set.
Just as with bases and nonbases, circuits are stored via their indices (rather than the elements of the ground set themselves).
i1 : M = matroid({a,b,c,d},{{a,b},{a,c}}) o1 = a matroid of rank 2 on 4 elements o1 : Matroid |
i2 : circuits M o2 = {set {1, 2}, set {3}} o2 : List |
The object circuits is a method function.