I am reading a book on chaos theory by Robert M.May.There is a reference to a 'minimal model of a ecosystem' through which the author describes hysteresis and bistable states. Q. What does a minimal model mean in mathematical terms,&also intuitively?Is it a concept of topology referring to homotopy between topological spaces or does it take another definitions? Q. How does one arrive at a 'minimal model equation' from a system of differential equations?