A local–global principle for vertex-isoperimetric problems
We consider the vertex-isoperimetric problem (VIP) for cartesian powers of a graph G. A total order ≼ on the vertex set of G is called isoperimetric if the boundary of sets of a given size k is minimum for any initial segment of ≼, and the ball around any initial segment is again an initial segment...
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Published in | Discrete mathematics Vol. 257; no. 2; pp. 285 - 309 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
Elsevier B.V
28.11.2002
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Subjects | |
Online Access | Get full text |
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Summary: | We consider the vertex-isoperimetric problem (VIP) for cartesian powers of a graph
G. A total order ≼ on the vertex set of
G is called isoperimetric if the boundary of sets of a given size
k is minimum for any initial segment of ≼, and the ball around any initial segment is again an initial segment of ≼. We prove a local–global principle with respect to the so-called simplicial order on
G
n
(see Section 2 for the definition). Namely, we show that the simplicial order ≼
n
is isoperimetric for each
n⩾1 iff it is so for
n=1,2. Some structural properties of graphs that admit simplicial isoperimetric orderings are presented. We also discuss new relations between the VIP and Macaulay posets. |
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ISSN: | 0012-365X 1872-681X |
DOI: | 10.1016/S0012-365X(02)00431-4 |