Abstract
We introduce the following notion: a digraph \(D=(V,A)\) with arc weights \(c: A\rightarrow {\mathbb {R}}\) is called nearly conservative if every negative cycle consists of two arcs. Computing shortest paths in nearly conservative digraphs is NP-hard, and even deciding whether a digraph is nearly conservative is coNP-complete.
We show that the “All Pairs Shortest Path” problem is fixed parameter tractable with various parameters for nearly conservative digraphs. The results also apply for the special case of conservative mixed graphs.
Zoltán Király—Research was supported by grants (no. CNK 77780 and no. K 109240) from the National Development Agency of Hungary, based on a source from the Research and Technology Innovation Fund.
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Acknowledgment
The author is thankful to András Frank who asked a special case of this problem, and also to Dániel Marx who proposed the generalization to nearly conservative digraphs.
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Király, Z. (2014). Shortest Paths in Nearly Conservative Digraphs. In: Cygan, M., Heggernes, P. (eds) Parameterized and Exact Computation. IPEC 2014. Lecture Notes in Computer Science(), vol 8894. Springer, Cham. https://doi.org/10.1007/978-3-319-13524-3_20
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DOI: https://doi.org/10.1007/978-3-319-13524-3_20
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