Two metrics in a graph theory modeling of organic chemistry

Balai, V., V. KvasniEka and J. Pospichal, Two metrics in a graph theory modeling of organic chemistry, Discrete Applied Mathematics 35 (1992) 1-19. Two different metrics in the graph theory model of organic chemistry are defined. The chemical distance between two graphs (molecules) taken from the same family of isomeric graphs S, (where p is a number of vertices and q is a number of edges and loops) is based on the maximal common subgraph. The reaction distance assigned to a transformation G = G’, where G, G’E S,, is equal to the minimal number of the so-called elementary transformations that are necessary for the transformation of G onto G’. Both the suggested met-its reflect formally many known fundamental chemical rules, in particular, the principle of minimal structural change.