Advanced matroid functionality.

This module collects a number of advanced functions which are not directly available to the end user by default. To import them into the main namespace, type:

sage: from sage.matroids.advanced import *

This adds the following to the main namespace:

• Matroid classes:

  • MinorMatroid

  • DualMatroid

  • RankMatroid

  • CircuitClosuresMatroid

  • BasisMatroid

  • LinearMatroid

  • RegularMatroid

  • BinaryMatroid

  • TernaryMatroid

  • QuaternaryMatroid

  • GraphicMatroid

Note that you can construct all of these through the Matroid() function, which is available on startup. Using the classes directly can sometimes be useful for faster code (e.g. if your code calls Matroid() frequently).

• Other classes:

  • LinearSubclasses

  • MatroidExtensions

Instances of these classes are returned by the methods Matroid.linear_subclasses() and Matroid.extensions().

• Useful functions:

  • setprint()

  • newlabel()

  • get_nonisomorphic_matroids()

  • lift_cross_ratios()

  • lift_map()

AUTHORS:

• Stefan van Zwam (2013-04-01): initial version