PI INDEX OF SOME BENZENOID GRAPHS
The Padmakar-Ivan (PI) index of a graph G is defined as PI(G) = ∑[neu(e|G)+ n ev(e|G)], where neu(e|G) is the number of edges of G lying closer to u than to v, n ev(e|G) is the number of edges of G lying closer to v than to u and summation goes over all edges of G. In this paper, we first compute the PI index of a class of pericondensed benzenoid graphs consisting of n rows, n ≤ 3, of hexagons of various lengths. Finally, we prove that for any connected graph G with exactly m edges, PI(G) ≤ m(m-1) with equality if and only if G is an acyclic graph or a cycle of odd length
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| Main Authors: | , |
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| Format: | Digital revista |
| Language: | English |
| Published: |
Sociedad Chilena de Química
2006
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| Online Access: | http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072006000300008 |
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