Displaying similar documents to “Non-surjective linear transformations of tropical matrices preserving the cyclicity index”

The i-chords of cycles and paths

Terry A. McKee (2012)

Discussiones Mathematicae Graph Theory

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An i-chord of a cycle or path is an edge whose endpoints are a distance i ≥ 2 apart along the cycle or path. Motivated by many standard graph classes being describable by the existence of chords, we investigate what happens when i-chords are required for specific values of i. Results include the following: A graph is strongly chordal if and only if, for i ∈ {4,6}, every cycle C with |V(C)| ≥ i has an (i/2)-chord. A graph is a threshold graph if and only if, for i ∈ {4,5}, every path...

On The Determinant of q-Distance Matrix of a Graph

Hong-Hai Li, Li Su, Jing Zhang (2014)

Discussiones Mathematicae Graph Theory

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In this note, we show how the determinant of the q-distance matrix Dq(T) of a weighted directed graph G can be expressed in terms of the corresponding determinants for the blocks of G, and thus generalize the results obtained by Graham et al. [R.L. Graham, A.J. Hoffman and H. Hosoya, On the distance matrix of a directed graph, J. Graph Theory 1 (1977) 85-88]. Further, by means of the result, we determine the determinant of the q-distance matrix of the graph obtained from a connected...

Spectra of expansion graphs.

Friedland, Shmuel, Schneider, Hans (1999)

ELA. The Electronic Journal of Linear Algebra [electronic only]

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On long cycles through four prescribed vertices of a polyhedral graph

Jochen Harant, Stanislav Jendrol', Hansjoachim Walther (2008)

Discussiones Mathematicae Graph Theory

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For a 3-connected planar graph G with circumference c ≥ 44 it is proved that G has a cycle of length at least (1/36)c+(20/3) through any four vertices of G.