Hi Anne, Nicolas M. Thiery wrote: > On Sat, Feb 13, 2010 at 09:53:27AM -0800, Anne Schilling wrote: >> I would like to write a symmetric polynomial (not function) >> in terms of one of the usual bases (like Schur polynomials).
> That's a quite basic feature, that we ought to have (that was fromPoly > in MuPAD-Combinat). But I fear we don't. At least I could not find it > browsing through the sources. I don't know of the existence of such a function. I've written a very quick-and-dirty (and very minimally tested) function below. If someone opens a ticket, I will try to get a proper version of this into sage at some point. Cheers, Jason def toSF(f): """ Input is a symmetric polynomial in a polynomial ring in finitely many variables. Output is a symmetric function in the monomial basis of the ring of symmetric functions over the same base ring. """ X = f.parent().gens() n = f.parent().ngens() SF = SymmetricFunctions(f.base_ring()) m = SF.monomial() out = m(0) while f != 0: lt = f.lt() c = lt.monomial_coefficient(lt) p = Partition(lt.exponents()[0]) f += -m(p).expand(n,X) out += c*m(p) return out -- You received this message because you are subscribed to the Google Groups "sage-combinat-devel" group. To post to this group, send email to sage-combinat-de...@googlegroups.com. To unsubscribe from this group, send email to sage-combinat-devel+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sage-combinat-devel?hl=en.