Topological factor definition

The topological factors Tpq were determined for the single-reference case considering all singles and doubles interacting with the reference. We need the following definitions (compare with nomenclature) ... 

The Introduction will give a brief description of DNA as a biopolymer (structure, conformations, topologies), some definitions in the field of polyelectrolytes (weak and strong polyelectrolytes), some generalities about DNA/ polycation complexes (factors influencing the complexation, models describing the structure of the polyplexes, methods adapted to their characterization), and a description of the parameters to take into consideration for their use in gene therapy. 

From their definitions, one may admit that topological indices may code two structural factors, namely, the size and the shape of the molecule. This assumption is proved by calculating 94) the schemes (B) in Figure 2 for the 36 polyalkylcyclohexanes with 6-10 carbon atoms, and for a subseries of 22 polyalkylcyclohexanes with 10 carbon atoms (resulting in scheme (C)). The schemes (A)-(C) corroborated with the... 

The choice of the factor 1 /2 in the definition of the combined operator implies that the graph symmetry factor follows immediately from considering the point y as a vertex therefore, the symmetry factor can be determined from the graph topology (see Figure 2.59 and the factors in the summands of Equation 135). 

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