Article ID Journal Published Year Pages File Type
10118314 European Journal of Combinatorics 2005 15 Pages PDF
Abstract
We study the vertices and facets of the polytopes of partitions of numbers. The partition polytope Pn is the convex hull of the set of incidence vectors of all partitions n=x1+2x2+⋯+nxn. We show that the sequence P1,P2,…,Pn,… can be treated as an embedded chain. The dynamics of behavior of the vertices of Pn, as n increases, is established. Some sufficient and some necessary conditions for a point of Pn to be its vertex are proved. Representation of the partition polytope as a polytope on a partial algebra-which is a generalization of the group polyhedron in the group theoretic approach to the integer linear programming-allows us to prove subadditive characterization of the nontrivial facets of Pn. These facets ∑i=1npixi≥p0 correspond to extreme rays of the cone of subadditive functions p:{1,2,…,n}→R with additional requirements p0=pn and pi+pn−i=pn,1≤i
Related Topics
Physical Sciences and Engineering Mathematics Discrete Mathematics and Combinatorics
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