If the integral polynomial is not monic then the roots need not be integral:
sage: R.<x> = QQ[] sage: (4*x^2-1).factor() (4) * (x - 1/2) * (x + 1/2) So this would not be factorizable in ZZ[x] but is factorizable in QQ[x] On Friday, October 4, 2013 12:44:41 PM UTC+1, Jori Mantysalo wrote: > > $SAGE_ROOT/devel/sage-main/sage/rings/polynomial/multi_polynomial_libsingular.pyx > > > contains > > if not self._parent._base.is_field(): > raise NotImplementedError, "Factorization of multivariate polynomials > over non-fields is not implemented." > > It seems trivial to have at least working (but maybe slow) fix for ZZ: > > if not self._parent._base.is_field(): > if > type(self._parent._base)==sage.rings.integer_ring.IntegerRing_class: > return sage.structure.factorization.Factorization ( [ > (t[0].change_ring(sage.rings.integer_ring.ZZ), t[1]) for t in > self.change_ring(sage.rings.rational_field.QQ).factor(proof) ] ) > else: > raise NotImplementedError, "Factorization of multivariate > polynomials over non-fields (except ZZ) is not implemented." > > However, this sounds TOO easy. Is there some untriviality lying somewhere? > > -- > Jori M�ntysalo > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/groups/opt_out.
