Fig. 2: Mathematical basis for matrix-encoded molecular structures and reactions.
From: Exploring the combinatorial explosion of amine–acid reaction space via graph editing

a Demonstration of matrix-encoding of reaction from panel 1a. In the molecular diagrams, white circles represent carbon, blue circles nitrogen, and red circles oxygen. The numbers in the adjacency matrix correspond to the atom indices in the cartoon atoms, while the color represents bond order. b Workflow for exhaustive generation of amine–acid coupling products. c The difference between the product matrix and starting material matrix is the transformation matrix.