topological distance and Li = L0,i −NH,i + qi is a local atom index (a characteristics of atom i) calculated from the atom valence, L0,i, the number of hydrogen atoms attached to atom, NH,i, and qi which is the corresponding charge density. The partial charges are computed by the topological empirical method of Gasteiger-Marsili [2] calculated with a fixed number of iterations. The CTI index co...

We generalize the coincidence semi-index introduced in [D-J] to pairs of maps between topological manifolds. This permits extending the Nielsen theory to this class of maps. Introduction. In this paper we generalize the coincidence semi-index theory, introduced in [D-J] in the smooth case, to pairs of maps between topological manifolds. It will be based on the topological transversality lemma (...

Among topological descriptors connectivity topological indices are very important and they have a prominent role in chemistry. One of them is atom-bond connectivity (ABC) index defined as ABC(G)= [formula:see text], in which degree of vertex v denoted by dv . Recently, a new version of atom-bond connectivity (ABC4) index was introduced by M. Ghorbani et.al in 2010 and is defined as ABC4(G)= [fo...

Hopf insulators are characterized by a topological invariant called the Hopf index which classifies maps from three-sphere to two-sphere, instead of a Chern number or a Chern parity. In contrast to a topological insulator, the Hopf insulator is not protected by any kind of symmetry. By dimensional reduction, we argue that there exists a new type of Z(2) index for 2D Hamiltonian with a vanishing...

Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. In this paper we introduce four Z 2 topological indices ␨ k =0,1 at k = ͑0,0͒, ͑0,␲͒, ͑␲ ,0͒, and ͑␲ , ␲͒ characterizing 16...

We discuss the Witten index in terms of Krein's spectral shift function, and prove invariance of the Witten index under suitable relative trace class hypotheses.

During the last two decades a large number of numerical graph invariants (topological indices) have been defined and used for correlation analysis in theoretical chemisty, pharmacology, toxicology, and environmental chemistry. However, no systematic study has been undertaken to determine to what extent these indices are correlated with each other. In the present paper we have carried out a prin...

The intercorrelation between a series of physicochemical parameters and topological indices for a set of beta-blockers is investigated. Partition coefficients are calculated using the ClogP program, and the results are compared with previous data, both experimental and theoretical. These data are complemented by hydrophilicity and solubility calculations, together with the determination of mole...