Canonical numbering

The methine carbon atom also obtains an EC value of 4 (= 1 -h 1 + 2) in the second iteration. This process is repeated iteratively until the number of different EC values (c) is lower than or equal to the number of EC values in the previous iteration. Then the relaxation procc.ss is terminated. Next, the EC numbers of the previous iteration are taken for a canonical numbering and for the determination of constitutional symmetry (Figure 2-44),... 

Figure 8A-1. InChl for guanine (A) input structure (B) mobile H canonical numbering, with the attachment points of four mobile H and changeable bonds indicated in bold and (C) with fixed H canonical numbering.

Canonical Numbering. Reordering the numbering of atoms in a structure to a unique order, based on the extended counting of the number of attachments at each center the atom and bond types, etc. 

Equivalence Class. In the canonicalization of structures that have some element of symmetry, certain atoms that are topologically equivalent may yield the same canonical number. These atoms are considered to be in the same equivalence class. The concept of equivalence class is used, for example, in the Daylight Chemical Information Systems handling of reactions, to examine equivalent atoms when mapping reactant and product atoms. 

Moreover, the coefficients of the eigenvector associated with the largest eigenvalue were used by Randic for - canonical numbering of graph vertices. 

HOC algorithms hierarchically ordered extended connectivities algorithms - canonical numbering... 

Jochum-Gasteiger canonical numbering canonical numbering Joshi electronic descriptors... 

Local vertex invariants are used to calculate several molecular - topological indices by applying different operators such as addition of LOVIs, addition of squares of LOVIs, addition of reciprocal geometric means for any pair of adjacent vertices. Moreover, they can be used to obtain - canonical numbering of molecular graphs and compare molecules in order to study - molecular branching and centricity. 

Topological atomic charges provide a canonical numbering of graph vertices, each vertex being ordered according to its branching, centrality and cyclicity. 

---