On 18 November 2014 13:38, Soli vishkautsan <wish...@gmail.com> wrote: > I am trying to compose 3 affine automorphisms of the Markoff surface. > The following code produces an error: > > A.<x,y,z> = AffineSpace(QQ,3) > M = A.subscheme([x^2+y^2+z^2-3*x*y*z]) > H = Hom(M,M) > f1 = H([3*y*z-x,y,z]) > f2 = H([x,3*x*z-y,z]) > f3 = H([x,y,3*x*y-z]) > f3*f2*f1 > > What am I doing wrong?
This could be a bug. Both f3*f2 and f2*f1 work ok, returning "Composite maps". Also (f3*f2)*(f2*f1) works (not what you want of course. It looks to me as if the people who implemented Composite maps did not define the * operator to work with a combination of Composite and ordinary maps. Silly workaround: sage: id = H([x,y,z]) sage: (f3*f2)*(f1*id) Composite map: From: Closed subscheme of Affine Space of dimension 3 over Rational Field defined by: -3*x*y*z + x^2 + y^2 + z^2 To: Closed subscheme of Affine Space of dimension 3 over Rational Field defined by: -3*x*y*z + x^2 + y^2 + z^2 Defn: Generic endomorphism of Closed subscheme of Affine Space of dimension 3 over Rational Field defined by: -3*x*y*z + x^2 + y^2 + z^2 then Generic endomorphism of Closed subscheme of Affine Space of dimension 3 over Rational Field defined by: -3*x*y*z + x^2 + y^2 + z^2 then Generic endomorphism of Closed subscheme of Affine Space of dimension 3 over Rational Field defined by: -3*x*y*z + x^2 + y^2 + z^2 then Generic endomorphism of Closed subscheme of Affine Space of dimension 3 over Rational Field defined by: -3*x*y*z + x^2 + y^2 + z^2 John Cremona > > -- > You received this message because you are subscribed to the Google Groups > "sage-support" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sage-support+unsubscr...@googlegroups.com. > To post to this group, send email to sage-support@googlegroups.com. > Visit this group at http://groups.google.com/group/sage-support. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.