Variations of the Connectivity Index

In several studies, the connectivity index has been based on alternative characterizations of heteroatoms as will be briefly outlined in the next section. Here we will describe a modification of the connectivity index that is of a mathematical nature 

Note The two numerical columns list the contributions of paths of length two to 

FIGURE 6.4 Graph on 20 vertices for which Table 6.11 has listed all paths of lengths two and their contrihutions to the second-order generalized connectivity index. 

we would like to comment on mathematical modification, not of the connectivity index, but the higher-order connectivity indices. 

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