relaxation(M, S)
relaxation M
Let M = (E, B) be a matroid with bases B. If there is a subset S of E that is both a circuit and a hyperplane of M, then the set $B \cup \{S\}$ is the set of bases of a matroid on E, called the relaxation of M by S.
If no set S is provided, then this function will take S to be a random circuithyperplane (the first in lexicographic order). If no circuithyperplanes exist, then an error is produced.
Many interesting matroids arise as relaxations of other matroids: e.g. the nonFano matroid is a relaxation of the Fano matroid, and the nonPappus matroid is a relaxation of the Pappus matroid.



The object relaxation is a method function with options.