Economy and dynamical equations

The great difference between the bourgeois economy and Marx's economy is not in the class-character of Marx's ideas, but in the fact that the economy of Marx is dynamici, whereas mainstream economy is static.Dynamics is represented in mathematics with differential equations, and there is no trace of differential equations in mainstream economy (at least to my knowledge), wherteas it would be rather easy to express the ideas of "Das Kapital" in terms of differential equations.