Forced pairs in A-Stick graphs
| Autor: | Rusu, Irena |
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| Rok vydání: | 2021 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | A Stick graph G=(A\cup B, E) is the intersection graph of a set A of horizontal segments and a set B of vertical segments in the plane, whose left and respectively bottom endpoints lie on the same ground line with slope -1. These endpoints are respectively called A-origins and B-origins. When a total order is provided for the A-origins, the resulting graphs are called A-Stick graphs. In this paper, we propose a characterization of the class of A-Stick graphs using forced pairs, which are pairs of segments in B with the property that only one left-to-right order of their origins is possible on the ground line. We deduce a recognition algorithm for A-Stick graphs running in O(|A|+|B|+|E|) time, thus improving the running time of O(|A|\cdot |B|) of the best current algorithm. We also introduce the problem of finding, for a Stick graph, a representation using segments of minimum total length. The canonical order on the A- and B-origins, output by our recognition algorithm, allows us to obtain partial results on this problem. Comment: 26 pages, 3 figures |
| Databáze: | arXiv |
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