The Facets of the Bases Polytope of a Matroid and Two Consequences

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DOI: 10.4236/ojdm.2018.81002    752 Downloads   1,370 Views  Citations
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ABSTRACT

Let M be a matroid defined on a finite set E and L ⊂ E . L is locked in M if  and  are 2-connected, and . In this paper, we prove that the nontrivial facets of the bases polytope of M are described by the locked subsets. We deduce that finding the maximum-weight basis of M is a polynomial time problem for matroids with a polynomial number of locked subsets. This class of matroids is closed under 2-sums and contains the class of uniform matroids, the Vámos matroid and all the excluded minors of 2-sums of uniform matroids. We deduce also a matroid oracle for testing uniformity of matroids after one call of this oracle.

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Chaourar, B. (2018) The Facets of the Bases Polytope of a Matroid and Two Consequences. Open Journal of Discrete Mathematics, 8, 14-20. doi: 10.4236/ojdm.2018.81002.

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