Include file:

#include "mcrl2/data/substitutions/maintain_variables_in_rhs.h"

This class extends a substitution to recall the variables that occur in its right hand side. It assumes the presence of an operation sigma[x]=v to set values of a variable. If sigma[x]=x, this is seen as clearing the variable, and x is not recalled. The variables recalled are an overapproximation. By regular garbage collection the