The structure of the 4-separations in 4-connected matroids
For a 2-connected matroid M, Cunningham and Edmonds gave a tree decomposition that displays all of its 2-separations. When M is 3-connected, two 3-separations are equivalent if one can be obtained from the other by passing through a sequence of 3-separations each of which is obtained from its predecessor by moving a single element from one side of the 3-separation to the other. Oxley, Semple, and Whittle gave a tree decomposition that displays, up to this equivalence, all non-trivial 3-separations of M. Now let M be 4-connected. In this paper, we define two 4-separations of M to be 2-equivalent if one can be obtained from the other by passing through a sequence of 4-separations each obtained from its predecessor by moving at most two elements from one side of the 4-separation to the other. The main result of the paper proves that M has a tree decomposition that displays, up to 2-equivalence, all non-trivial 4-separations of M. © 2011 Elsevier Inc. All rights reserved.
Publication Source (Journal or Book title)
Advances in Applied Mathematics
Aikin, J., & Oxley, J. (2012). The structure of the 4-separations in 4-connected matroids. Advances in Applied Mathematics, 48 (1), 1-24. https://doi.org/10.1016/j.aam.2011.06.001