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词汇 Combinatorial map
分类 英语词汇 英语翻译词典
释义

Combinatorial map

英语百科

Combinatorial map

A plane graph
Corresponding combinatorial map (D, σ, α). Darts are represented by numbered segments, σ by gray arrows (example σ(1)=7), two darts linked by α are drawn consecutively and separated by a small bar (example α(1)=2).
Corresponding combinatorial map (D, φ, α). Darts are represented by numbered arrows, two darts linked by φ are drawn consecutively (example φ(1)=3) and two darts linked by α are drawn parallel and in reverse orientation (example α(1)=2).

A combinatorial map is a combinatorial object modelling topological structures with subdivided objects. Historically, the concept was introduced informally by J. Edmonds for polyhedral surfaces which are planar graphs. It was given its first definite formal expression under the name "Constellations" by A. Jacques but the concept was already extensively used under the name "rotation" by Gerhard Ringel and J.W.T. Youngs in their famous solution of the Heawood map-coloring problem. The term "constellation" was not retained and instead "combinatorial map" was favored. The concept was later extended to represent higher-dimensional orientable subdivided objects. Combinatorial maps are used as efficient data structures in image representation and processing, in geometrical modeling. This model is related to simplicial complexes and to combinatorial topology. Note that combinatorial maps were extended to generalized maps that allow also to represent non-orientable objects like the Möbius strip and the Klein bottle. A combinatorial map is a boundary representation model; it represents object by its boundaries.

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