loops M
The loops of a matroid are the one-element circuits.
i1 : M = matroid({a,b,c,d},{{a,b},{a,c}}) o1 = a "matroid" of rank 2 on 4 elements o1 : Matroid
i2 : loops M o2 = {3} o2 : List
i3 : all(loops M, l -> member(set{l}, circuits M)) o3 = true
i4 : loops(M/(set loops M)) == {} o4 = true
The object loops is a method function.