Abstract
We show that the symmetry groups of the cut cone Cutn and the metric cone Metn both consist of the isometries induced by the permutations on {1,...,n]; that is, I s(Cutn) = I s(Metn) ≃ Sym(n) for n ≥. For n = 4 we have I s(Cut4) = I s(Met 4) ≃ Sym(3) × Sym(4). This result can be extended to cones containing the cuts as extreme rays and for which the triangle inequalities are facet-inducing. For instance, I s(Hypn) ≃ Sym(n) for n ≥ 5, where Hypn denotes the hypermetric cone.
Original language | English (US) |
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Pages (from-to) | 197-203 |
Number of pages | 7 |
Journal | Journal of Algebraic Combinatorics |
Volume | 23 |
Issue number | 2 |
DOIs | |
State | Published - Mar 2006 |
Externally published | Yes |
Funding
The first author is partially supported by the NSREC under the Canada Research Chair and the Discovery Grant programs. The work was completed while the third author held a position at CS Dept. of University of Frankfurt, supported by the DFG Grant SCHN-503/2-1. The second and the third author acknowledge support by the Research School SOM of the University of Groningen.
Keywords
- Hypermetric cone
- Metric cone
- Polyhedral combinatorics
- Symmetry group
ASJC Scopus subject areas
- Algebra and Number Theory
- Discrete Mathematics and Combinatorics