Oct 21, 2009
Alexander Engström (Berkeley): Topological representations of matroids
Abstract:
In the theory of oriented matroids one of the basic tools is the old
topological representation theorem. It was common wisdom that this
couldn't be done for ordinary matroids until Ed Swartz proved that it
actually could be done.
We give a conceptual new way to find topological representations of
matroids. They are homotopy colimits of diagrams of spaces, and the
diagrams are geometric lattices of matroids.