✦ LIBER ✦

The PI Index of polyomino chains

✍ Scribed by Lixing Xu; Shubo Chen

Publisher: Elsevier Science
Year: 2008
Tongue: English
Weight: 213 KB
Volume: 21
Category: Article
ISSN: 0893-9659
DOI: 10.1016/j.aml.2007.12.007

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✦ Synopsis

The PI index is a graph invariant defined as the summation of the sums of n eu (e|G) and n ev (e|G) over all the edges e = uv of a connected graph G, i.e., PI(G) = e∈E(G) [n eu (e|G) + n ev (e|G)], where n eu (e|G) is the number of edges of G lying closer to u than to v and n ev (e|G) is the number of edges of G lying closer to v than to u. An efficient formula for calculating the PI index of polyomino chains is given, and the bounds for the PI index of polyomino chains are established.

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