Figure 6. Schematics of A) 6-variable and B) 4-variable reduced models.

The species calculated with differential equations are opaque, while the rest are faded. Compare with the 25-variable schematic (Figure 2). The 4-variable model has two less differential equations, represented by the further fading of TnI and PLB. Reduced (faded) species from the original 25-variable model are still predicted in the reduced models, but using explicit algebraic rather than differential or implicit algebraic equations.