J. Dugundji Department of Mathematics, University of So. Cal., Los Angeles, CA. 90007, USA Z. Naturforsch. 37 b, 1205-1215 (1982); received April 5, 1982 Chemical Topology, Structure Correlation, Measure of Chemical Similarity, Quality of Syntheses, Shortest Reaction Pathways The principle of minimum chemical distance (PMCD) is derived from the general theory of the BEand R-matrices, and makes ...