"Sphere Representations, Stacked Polytopes, and the Colin de Verdière N" by Lon Mitchell and Lynne Yengulalp
 

USF St. Petersburg Campus Faculty Publications

Sphere Representations, Stacked Polytopes, and the Colin de Verdière Number of a Graph

SelectedWorks Author Profiles:

Lon Mitchell

Document Type

Article

Publication Date

2016

ISSN

1077-8926

Abstract

We prove that a k -tree can be viewed as a subgraph of a special type of ( k + 1 ) -tree that corresponds to a stacked polytope and that these "stacked'' ( k + 1 ) -trees admit representations by orthogonal spheres in R k + 1 . As a result, we derive lower bounds for Colin de Verdière's μ of complements of partial k -trees and prove that μ ( G ) + μ ( ¯¯¯¯ G ) ≥ | G | − 2 for all chordal G .

Publisher

The Electronic Journal of Combinatorics

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