Example for the creation of an abstract syntax graph of a small model. This figure displays a unified representation of kinetic equations from an example model that consists of the following reactions:. Both reactions are part of the glycolysis. The contained molecules are fructose 1,6-bisphosphate (F1,6BP), dihydroxyacetone phosphate (DHAP), and glyceraldehyde 3-phosphate (GA3P). Using the program SBMLsqueezer the following mass action kinetics have been created: [ DHAP]−k−2·[ GA3P]. The nodes for [DHAP] and [GA3P] are only contained in the syntax graph once and connected to more than one multiplication node. This figure clearly indicates that the syntax graph is not a tree. As can be seen in this picture, the outdegree of syntax trees does not have to be binary.