> > Thank you, that takes me a step further. If I formulate the solution for > my self I would say: take the symbolic expression, turn it into a > polynomial by the method 'polynomial', then turn it into a power series by > the proper substitution. That solves my original problem. It is nice to > talk to someone about these things! >
Hopefully I am allowed to ask a next question regarding dealing with power series. Suppose I have a power series in x1 and x2: f=x1*x2+O(x^3). If I substitute x1=y^2 and x2=y^2 I turn this into a power series in y: g(y) =y^4+O(y^6). Doing this in Sage in the following way: R.<x1,x2>=PowerSeriesRing(SR) Y.<y>=PowerSeriesRing(SR) f= x1*x2+R.O(3) g=f.substitute(x1=y^2,x2=y^2);g O(y^3) does not work. Is there a way to make Sage understand that O(x^2) becomes O(y^6) under the substitution x=y^2 (and in general under similar substitutions)? -- You received this message because you are subscribed to the Google Groups "sage-support" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sage-support?hl=en.
