A132043 Number of bitransversal (transversal and dual transversal) matroids on n unlabeled elements.

2, 4, 8, 17, 38, 95, 268, 917, 4086

Offset: 1

Author

Gordon F. Royle, Oct 30 2007

Keywords

• nonn

Comments

A transversal matroid is a matroid whose independent sets are the partial transversals of a family of subsets of [1..n], while a bitransversal matroid is a transversal matroid whose dual is transversal. The principal (or fundamental) transversal matroids enumerated by A049312 form an important subset of bitransversal matroids.

References

• Jensen, P. M., Binary fundamental matroids. Algebraic methods in graph theory, Vol. I, II (Szeged, 1978), pp. 281-296, Colloq. Math. Soc. Janos Bolyai, 25, North-Holland, Amsterdam-New York, 1981

Crossrefs

Cf. A049312.