An advanced simplification/expansion/comparison algorithm. To use

    PolynomialCreator pc = new PolynomialCreator(jep);
    Node simp = pc.simplify(node);
    Node expand = pc.expand(node);
    boolean flag = pc.equals(node1,node2);
    int res = pc.compare(node1,node2);
    PNodeI poly = pc.createPoly(node);

## How it works

The basic idea is to reduce each equation to a canonical form based on a total ordering of the terms. For example a polynomial in `x` will always be in the form `a+b x+c x^2+d x^3.` This makes comparison of two polynomials easy as it is just necessary to compare term by term, whereas it is difficult to compare `x^2-1` with `(x+1)*(x-1)` without any simplification or reordering.

The precise total ordering is intentionally not defined as it may be later modified. As an illustration some of the rules for the ordering are `0<1<2`, `5<x`, `x<x^2<x^3`, `x<y`.

A polynomial is constructed from a set of monomials by arranging the monomials in order. Likewise a monomial is constructed from a set of variables by arranging the variables in name order.

The algorithm can also work with non-polynomial equations. Functions are order by the name of the function and the ordering of their arguments. Hence `cos(x)<sin(x)<sin(y)`.