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Computing the zig-zag number of directed graphs
The notion of zig-zag number was introduced as an attempt to provide a unified algorithmic framework for directed graphs. Nevertheless, little was known about the complexity of computing this directed graph invariant. We prove that deciding whether a directed graph has zig-zag number at most k is in...
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Published in: | Discrete Applied Mathematics 2022-05, Vol.312, p.86-105 |
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Main Authors: | , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites |
Online Access: | Get full text |
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Summary: | The notion of zig-zag number was introduced as an attempt to provide a unified algorithmic framework for directed graphs. Nevertheless, little was known about the complexity of computing this directed graph invariant. We prove that deciding whether a directed graph has zig-zag number at most k is in NP for each fixed k≥0. Although for most of the natural decision problems this is an almost trivial result, settling k-zig-zag number in NP is surprisingly difficult. In addition, we prove that 2-zig-zag number is already an NP-hard problem. |
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ISSN: | 0166-218X 1872-6771 |
DOI: | 10.1016/j.dam.2021.09.013 |