The Merrifield and Simmons Indices

Recently, Marrifield and Simmons 92) argued that the total number of the following subsets of the vertices or edges of a graph G  

The inspection of the results obtained for all connected graphs of up to six vertices motivates the conclusions collected in Table 2. 

These authors showed 92) that a and a are sensitive to chemically significant details of the molecular structure and that the bond strength pattern within a molecule correlates with the numbers of independent sets intersecting the different bonds. 

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