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Totally Split-Decomposable Metrics of Combinatorial Dimension Two
A. Dress1ㄛ K.T. Huber2, and V. Moulton3
1FSPM-Strukturbildungsprozesse, University of Bielefeld, D-33501 Bielefeld, Germany
2Institute of Fundamental Sciences, Massey University, Private Bag 11 222, Palmerston North, New Zealand
3FMI, Mid Sweden University, Sundsvall, S 851-70, Sweden
Annals of Combinatorics 5 (1) p.99-112 March, 2001
AMS Subject Classification: 04A03, 04A20, 05C99, 52B99, 92B99
The combinatorial dimension of a metric space (X , d), denoted by dimcombin(d), arises naturally in the subject of T-theory, and, in case X is finite, corresponds with the (topological) dimension of the tight span associated to d. Metric spaces of combinatorial dimension at most one are well understood; they are precisely the metric spaces that can be embedded into $ \mathbb{R}$-trees. However, the structure of metric spaces of higher dimension is not so well understood. Indeed, even 2-dimensional finite metric spaces can have a rich structure.
       In this paper, we study finite metric spaces of combinatorial dimension two that are, in addition, totally split decomposable. In particular, we give several characterizations of such metrics derived through the study of a certain map that relates the tight span of a totally split-decomposable metric with its Buneman complex.
Keywords: metric space, consistent metric, tight span, combinatorial dimension, Buneman complex, split system, compatibility, incompatibility, weakly compatible, 2-compatible, k-compatible, 3-crossfree


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