Abstract
In this note we prove: let D be a 2-strong digraph of order \(n\) such that its \(n - 1\) vertices have degrees at least \(n + k\) and the remaining vertex \(z\) has degree at least \(n - k - 4,\) where \(k\) is a nonnegative integer. If \(D\) contains a cycle of length at least \(n - k - 2\) passing through \(z,\) then \(D\) is Hamiltonian. This result is best possible in some sense.
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ACKNOWLEDGMENTS
I am grateful to Professor Gregory Gutin for motivating me to present the complete proof of Theorem 8. Also thanks to Dr. Parandzem Hakobyan for formatting the manuscript of this paper.
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This work was supported by ongoing institutional funding. No additional grants to carry out or direct this particular research were obtained.
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Samvel Kh. Darbinyan (born on June 20, 1950) Candidate of Mathematics (Minsk, 1981), Associate Professor, Leading Researcher of “Institute for Informatics and Automation Problems of the National Academy of Sciences of the Republic of Armenia.” Areas of scientific interest: Graph theory (cycles and paths in digraphs), VLSI design. Author (coauthor) of more than 50 scientific works.
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Darbinyan, S.K. On Hamiltonian Cycles in a 2-Strong Digraphs with Large Degrees and Cycles. Pattern Recognit. Image Anal. 34, 62–73 (2024). https://doi.org/10.1134/S105466182401005X
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DOI: https://doi.org/10.1134/S105466182401005X