Matroids encode the concept of "(in)dependence" in an abstract way. You can define matroids via vector configurations or graphs, do basic conversions between different descriptions and perform basic operations such as deletions and contractions.
A matroid on the set {0,...,n-1}. Here n is the same as N_ELEMENTS.
Subsets of the ground set which form the bases of the matroid. Note that if you want to define a matroid via its bases, you should also specify N_ELEMENTS, because we allow matroids with loops.
Cocircuits (or bonds) of the matroid, i.e., minimal sets intersecting every basis.
Unique names assigned to the elements of the matroid.
For a matroid build from scratch, you should create this property by yourself. If you build the matroid with a construction client, (e.g. matroid_from_graph) the labels may be assigend for you in a meaningful way.
All subsets of the ground sets with cardinality RANK that are not bases.
Size of the ground set. The ground set itself always consists of the first integers starting with zero.
If the matroid is realizable over the rationals, this property contains (homogeneous) coordinates for some realization. Specifying coordinates is one way to define a matroid.
Polytope whose vertices are the characteristic vectors of the bases.
Tests whether the given bases do actually form the bases of a matroid.
Array<Set<Int>> | bases |
Bool | if set to true the output tells which condition fails;
default value is 0 |
Produce the tropical matroid polytope from a matroid m. Each vertex corresponds to a basis of the matroid, the non-bases coordinates get value 0, the bases coordinates gets value v, default is -1.
The matroid obtained from a matroid m by contraction of element .
Creates a graphical matroid from a graph g.
Creates a matroid from the corresponding matroid polytope p.
Creates the uniform matroid of rank r with n elements.