### Tuesday, July 14

## MS13

Matroid Representation

*Sponsored by the Canadian Mathematical Society*
10:30 AM-12:30 PM

*Room: Sidney Smith 1072*

Matroid representation theory addresses the question, given a field and a set of points with collection dependent subsets, under what conditions can the points be embedded into a vector space over the field in a way that respects the prescribed dependencies. This question is interesting in its own right, and also has applications in combinatorial optimization. The speakers in this minisymposium will provide an overview of progress made in the field in the last five years.

**Organizer: James F. Geelen**

*University of Waterloo, Canada*
**10:30 Generalized $\Delta$-Y Exchanges and $k$-Regular Matroids**
*James Oxley*, Louisiana State University; Charles Semple, Victoria University, New Zealand; and Dirk Vertigan, Louisiana State University
**11:00 Partial Fields**
- Dirk L. Vertigan, Louisiana State University
**11:30 Totally-free Expansions of Matroids**
*James F. Geelen*, Organizer; James G. Oxley and Dirk Vertigan, Louisiana State University; and Geoff P. Whittle, Victoria University, New Zealand
**12:00 A Splitter Theorem for 4-Connected Matroids**
- James F. Geelen, Organizer and Geoff P. Whittle, Victoria University, New Zealand

*MMD, 5/29/98*