Hall, R.Oxley, J.Semple, C.Whittle, G.2008-10-012008-10-012002Hall, R., Oxley, J., Semple, C., Whittle, G. (2002) On matroids of branch-width three. Journal of Combinatorial Theory, Series B, 86, pp. 148-171.http://hdl.handle.net/10092/1653For all positive integers k, the class Bk of matroids of branch-width at most k is minor-closed. When k is 1 or 2, the class Bk is, respectively, the class of direct sums of loops and coloops, and the class of direct sums of series- parallel networks. B3 is a much richer class as it contains infnite antichains of matroids and is thus not well-quasi-ordered under the minor order. In this paper, it is shown that, like B₁ and B₂, the class B₃ can be characterized by a nite list of excluded minorsenJournal ArticleFields of Research::230000 Mathematical Sciences::230100 Mathematics