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Graph Transmission


Let G be a connected graph with vertex set V(G) and graph distance d(u,v). The vertex transmission, or status, of a vertex u in V(G) is defined by

 T(u)=sum_(v in V(G))d(u,v).
(1)

Equivalently, if D=(d_(ij)) is the graph distance matrix of G, then the vector of vertex transmissions is

 T=D1,
(2)

where 1 is the all-ones vector. Thus the vertex transmissions are precisely the row sums of the graph distance matrix.

The diagonal matrix trs(G) having the vertex transmissions on its diagonal is used, for example, in defining transmission-adjacency matrices such as trs(G)-A and trs(G)+A, where A is the adjacency matrix (Alfaro et al. 2023).

The graph transmission of G is defined by

 T(G)=1/2sum_(u,v in V(G))d(u,v)=1/2sum_(u in V(G))T(u),
(3)

and is therefore identical to the Wiener index W(G).

For a graph on n vertices with mean distance d^_, the graph transmission satisfies

 T(G)=W(G)=(n^2)/2d^_,
(4)

and the average vertex transmission is

 1/nsum_(u in V(G))T(u)=(2T(G))/n=nd^_.
(5)

For connected graphs with n>1, the usual normalized closeness centrality C(u) is the reciprocal of the average distance from u to all other vertices, and hence

 C(u)=(n-1)/(T(u)).
(6)

The number of distinct vertex transmissions of G is called the transmission dimension. A graph whose vertices all have the same vertex transmission is called transmission-regular.


See also

Graph Distance, Graph Distance Matrix, Mean Distance, Transmission Dimension, Transmission-Regular Graph, Vertex Transmission, Wiener Index

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References

Alfaro, C. A.; Villagrán, R. R.; and Zapata, O. "Distinguishing Graphs with Two Integer Matrices." 27 Sep 2023. https://arxiv.org/abs/2309.15365.Sharon, J. O. and Rajalaxmi, T. M. "Transmission in Certain Trees." Procedia Comput. Sci. 172, 193-198, 2020. https://doi.org/10.1016/j.procs.2020.05.030.

Cite this as:

Weisstein, Eric W. "Graph Transmission." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/GraphTransmission.html

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