Maxima Function
fast_central_elements ([x_1, ..., x_n], n)
If set_up_dot_simplifications
has been previously done, finds the central polynomials
in the variables x_1, ..., x_n in the given degree, n.
For example:
set_up_dot_simplifications ([y.x + x.y], 3); fast_central_elements ([x, y], 2); [y.y, x.x];