2021/06/22 by Spiro, Sam · 1 citation
#05C12 #Combinatorics (math.CO) #FOS: Mathematics
paper · doi:10.48550/arxiv.2106.11869
The Wiener index of a graph W(G) is a well studied topological index for graphs. An outstanding problem of Šoltés is to find graphs G such that W(G)=W(G-v) for all vertices v∈ V(G), with the only known example being G=C11. We relax this problem by defining a notion of Wiener indices for signed graphs, which we denote by Wσ(G), and under this relaxation we construct many signed graphs such that Wσ(G)=Wσ(G-v) for all v∈ V(G). This ends up being related to a problem of independent interest, which asks when it is possible to 2-color the edges of a graph G such that there is a path between any two vertices of G which uses each color the same number of times.