I am looking at the system:

$2X + Y \Leftrightarrow 3X $

$A \rightarrow Y$

$X \rightarrow B$

The description in terms of differential equations is this:

$\frac{dx}{dt} = x^{2}y - x$

$\frac{dy}{dt} = a - x^{2}y$

What is puzzling me is that the fact that 3X are produced is not captured in these equations.

Why is the description not something like

$\frac{dx}{dt} = 3x^{2}y - x - x^{3}$ ?

What fundamental thing am I missing? Help is greatly appreciated.

I am looking at the system:

$2X + Y \Leftrightarrow 3X $

$A \rightarrow Y$

$X \rightarrow B$

The description in terms of differential equations is this:

$\frac{dx}{dt} = x^{2}y - x$

$\frac{dy}{dt} = a - x^{2}y$

What is puzzling me is that the fact that 3X are produced is not captured in these equations.

Why is the description not something like

$\frac{dx}{dt} = 3x^{2}y - x - x^{3}$ ?

What fundamental thing am I missing? Help is greatly appreciated.

(also, I have a hard time finding relevant tags for this, so please feel free to change)