I was reading about Marx's Crisis Theory. On one hand, there is this idea of the falling surplus. But on the other hand, he relates income inequality to the business cycle.
Have his ideas regarding the relation between inequality and the business cycle been formalized (mathematically)? Where can I read those? And are there other (Marxian or non-Marxian, including neo-classical/ Keynesian) mathematical models that relate income or wealth inequality and the business cycle? Where can I read those?