The model contains one compartment called "compartment". There are four species named S1, S2, S3 and S4 and three parameters named k1, k2 and k3. Compartment "compartment" is 0-dimensional. The model contains two reactions defined as:

Reaction Rate
S1 + S2 → S3 k1 · S1 · S2
S3 → S1 + S2 k2 · S3

The model contains one rule which assigns value to species S4:

Type Variable Formula
Assignment S4 k3 · S2

In this case there is no initial value declared for species S4 and thus it must be calculated by the assignmentRule. Note that since this assignmentRule must always remain true, it should be considered during simulation.

The initial conditions are as follows:

Value Units
Initial amount of S1: 1 × 10−3 mole
Initial amount of S2: 1.5 × 10−3 mole
Initial amount of S3: 1 × 10−3 mole
Initial amount of S4: undeclared mole
Value of parameter k1: 1.5 × 103 litre mole-1 second-1
Value of parameter k2: 50 second-1
Value of parameter k3: 1.5 dimensionless

In this example the compartment has its spatialDimensions attribute set to zero; i.e., it represents a point and therefore cannot have size or units. The species values must be treated as amounts and not concentrations.