Graphical matrices are presented. Their construction via selected sets of subgraphs and the replacement of subgraphs by numbers representing graph invariants are discussed. The last step of the procedure is to apply the method of choice for obtaining the desired double invariant from the graphical matrix in the numerical form. It is also pointed out that many so-called special graph-theoretical...

The kth power of a graph G, denoted by Gk , is a graph with the same vertex set as G such that two vertices are adjacent in Gk if and only if their distance is at most k in G. The Wiener index is a distance-based topological index defined as the sum of distances between all pairs of vertices in a graph. In this note, we give the bounds on the Wiener index of the graph Gk . The Nordhaus–Gaddum-t...

The Wiener index of a connected graph is the sum of topological distances between all pairs of vertices. Since Wang in [23] gave a mistake result on the maximum Wiener index for given tree degree sequence, in this paper, we investigate the maximum Wiener index of trees with given degree sequences and extremal trees which attain the maximum value.

The Wiener index of a graph is the sum of all pairwise distances of vertices of the graph. In this paper we characterize the trees which minimize the Wiener index among all trees of given order and maximum degree and the trees which maximize the Wiener index among all trees of given order that have only vertices of two di erent degrees.

In the drug design process, one wants to construct chemical compounds with certain properties. In order to establish the mathematical basis for the connections between molecular structures and physicochemical properties of chemical compounds, some so-called structure-descriptors or ”topological indices” have been put forward. Among them, the Wiener index is one of the most important. A long sta...

The Wiener index of a graph G, denoted W(G), is the sum distances between all non-ordered pairs vertices in G.É. Czabarka, et al. conjectured that for simple quadrangulation G on n vertices, n?4, W(G)?112n3+76n?2,n?0(mod2), 112n3+1112n?1,n?1(mod2).In this paper, we confirm conjecture.

Sediment dynamics and the hydrodynamics of the environment cause the complexity and variability in animal-sediment relationship, both in spatial and temporal. This study is focused on the response of macrobenthic fauna to environmental disturbance caused by fish farming using their trophic structure. Their changes in trophic structure can be used as an indicator of disturbance. Eight control si...