Strong arc decompositions of split digraphs

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Titel: Strong arc decompositions of split digraphs
Autoren: Jørgen Bang‐Jensen, Yun Wang
Quelle: Journal of Graph Theory. 108:5-26
Verlagsinformationen: Wiley, 2024.
Publikationsjahr: 2024
Schlagwörter: branchings, strong arc decomposition, 0211 other engineering and technologies, split digraph, 0102 computer and information sciences, 02 engineering and technology, semicomplete digraph, 01 natural sciences
Beschreibung: A strong arc decomposition of a digraph is a partition of its arc set into two sets such that the digraph is strong for . Bang‐Jensen and Yeo conjectured that there is some such that every ‐arc‐strong digraph has a strong arc decomposition. They also proved that with one exception on four vertices every 2‐arc‐strong semicomplete digraph has a strong arc decomposition. Bang‐Jensen and Huang extended this result to locally semicomplete digraphs by proving that every 2‐arc‐strong locally semicomplete digraph which is not the square of an even cycle has a strong arc decomposition. This implies that every 3‐arc‐strong locally semicomplete digraph has a strong arc decomposition. A split digraph is a digraph whose underlying undirected graph is a split graph, meaning that its vertices can be partitioned into a clique and an independent set. Equivalently, a split digraph is any digraph which can be obtained from a semicomplete digraph by adding a new set of vertices and some arcs between and . In this paper, we prove that every 3‐arc‐strong split digraph has a strong arc decomposition which can be found in polynomial time and we provide infinite classes of 2‐strong split digraphs with no strong arc decomposition. We also pose a number of open problems on split digraphs.
Publikationsart: Article
Sprache: English
ISSN: 1097-0118
0364-9024
DOI: 10.1002/jgt.23157
Rights: CC BY NC ND
Dokumentencode: edsair.doi.dedup.....0abd96459b2d4ce2232a9052ee337809
Datenbank: OpenAIRE
Beschreibung
Abstract:A strong arc decomposition of a digraph is a partition of its arc set into two sets such that the digraph is strong for . Bang‐Jensen and Yeo conjectured that there is some such that every ‐arc‐strong digraph has a strong arc decomposition. They also proved that with one exception on four vertices every 2‐arc‐strong semicomplete digraph has a strong arc decomposition. Bang‐Jensen and Huang extended this result to locally semicomplete digraphs by proving that every 2‐arc‐strong locally semicomplete digraph which is not the square of an even cycle has a strong arc decomposition. This implies that every 3‐arc‐strong locally semicomplete digraph has a strong arc decomposition. A split digraph is a digraph whose underlying undirected graph is a split graph, meaning that its vertices can be partitioned into a clique and an independent set. Equivalently, a split digraph is any digraph which can be obtained from a semicomplete digraph by adding a new set of vertices and some arcs between and . In this paper, we prove that every 3‐arc‐strong split digraph has a strong arc decomposition which can be found in polynomial time and we provide infinite classes of 2‐strong split digraphs with no strong arc decomposition. We also pose a number of open problems on split digraphs.
ISSN:10970118
03649024
DOI:10.1002/jgt.23157