Recognizing string graphs in NP
Recognizing string graphs in NP
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DOI:
10.1145/509907.509910
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发表时间:
2002-05
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影响因子:
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通讯作者:
M. Schaefer;E. Sedgwick;Daniel Stefankovic
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文献类型:
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作者:
M. Schaefer;E. Sedgwick;Daniel Stefankovic
A string graph is the intersection graph of a set of curves in the plane. Each curve is represented by a vertex, and an edge between two vertices means that the corresponding curves intersect. We show that string graphs can be recognized in NP. The recognition problem was not known to be decidable until very recently, when two independent papers established exponential upper bounds on the number of intersections needed to realize a string graph [18, 20]. These results implied that the recognition problem lies in NEXP. In the present paper we improve this by showing that the recognition problem for string graphs is in NP, and therefore NP-complete, since Kratochvíl [12] showed that the recognition problem is NP-hard. The result has consequences for the computational complexity of problems in graph drawing, and topological inference.