Rhiannon Hall, Dillon Mayhew, Stefan H. M. van Zwam
Published 2009-02-12, updated 2009-07-12Version 3
In unpublished work, Geelen proved that a matroid is near-regular if and only if it has no minor isomorphic to: U2,5; U3,5; the Fano plane and its dual; the non-Fano and its dual; the single-element deletion of AG(2,3), its dual, and the matroid obtained from it with a Delta-Y operation; and P8. We provide a proof of this characterization.
Comments: 42 pages and 3 figures. This final version contains some small changes for publication
An obstacle to a decomposition theorem for near-regular matroids
On the relative importance of excluded minors
On the co-degree threshold for the Fano plane
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