475 research outputs found
Manhattan orbifolds
We investigate a class of metrics for 2-manifolds in which, except for a
discrete set of singular points, the metric is locally isometric to an L_1 (or
equivalently L_infinity) metric, and show that with certain additional
conditions such metrics are injective. We use this construction to find the
tight span of squaregraphs and related graphs, and we find an injective metric
that approximates the distances in the hyperbolic plane analogously to the way
the rectilinear metrics approximate the Euclidean distance.Comment: 17 pages, 15 figures. Some definitions and proofs have been revised
since the previous version, and a new example has been adde
Conversations on a probable future: interview with Beatrice Fazi
No description supplie
Trees, Tight-Spans and Point Configuration
Tight-spans of metrics were first introduced by Isbell in 1964 and
rediscovered and studied by others, most notably by Dress, who gave them this
name. Subsequently, it was found that tight-spans could be defined for more
general maps, such as directed metrics and distances, and more recently for
diversities. In this paper, we show that all of these tight-spans as well as
some related constructions can be defined in terms of point configurations.
This provides a useful way in which to study these objects in a unified and
systematic way. We also show that by using point configurations we can recover
results concerning one-dimensional tight-spans for all of the maps we consider,
as well as extend these and other results to more general maps such as
symmetric and unsymmetric maps.Comment: 21 pages, 2 figure
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