Question regarding the rat-function (and "CRE" in general) re ratexpand specifically



ratexpand does exactly the same thing as rat() but then follows it with 
a pass over the expression that
is like ratdisrep, but constructs the result in an expanded form.

construction of x*y +x*z  instead of x*(y+z)  is a trivial alteration in 
the algorithm.

RJF