in this paper, at first we mention to some results related to pi and vertex co-pi indices and then we introduce the edge versions of co-pi indices. then, we obtain some properties about these new indices.

In this paper, at first we mention to some results related to PI and vertex Co-PI indices and then we introduce the edge versions of Co-PI indices. Then, we obtain some properties about these new indices.

the padmakar-ivan (pi) index is a first-generation topological index (ti) based on sums overall edges between numbers of edges closer to one endpoint and numbers of edges closer to theother endpoint. edges at equal distances from the two endpoints are ignored. an analogousdefinition is valid for the wiener index w, with the difference that sums are replaced byproducts. a few other tis are discu...

let g and h be two graphs. the corona product g o h is obtained by taking one copy of gand |v(g)| copies of h; and by joining each vertex of the i-th copy of h to the i-th vertex of g,i = 1, 2, …, |v(g)|. in this paper, we compute pi and hyper–wiener indices of the coronaproduct of graphs.

The Padmakar-Ivan (PI) index is a Wiener-Szeged-like topological index, which reflects certain structural features of organic molecules. In this paper, we study the maximum PI indices and the minimum PI indices for trees and unicyclic graphs respectively.

background: the p ulsatility index (pi) shows continuous blood flow to the end organs and is a significant factor believed to decrease in aortic coarctation. correction of this factor is of great importance in the treatment of stenotic lesions of the aorta. however, there are minimal data regarding the trend of changes in the pi after stent implantation. furthermore, the association between the...

BACKGROUND The pulsatility index (PI) shows continuous blood flow to the end organs and is a significant factor believed to decrease in aortic coarctation. Correction of this factor is of great importance in the treatment of stenotic lesions of the aorta. However, there are minimal data regarding the trend of changes in the PI after stent implantation. Furthermore, the association between the P...

Valence topological charge-transfer (CT) indices are applied to the calculation of pH at the pI isoelectric point. The combination of CT indices allows the estimation of pI. The model is generalized for molecules with heteroatoms. The ability of the indices for the description of molecular charge distribution is established by comparing them with the pI of 21 amino acids. Linear correlation mod...