Sorry, early weekend and the brain isn't working yet. The documentation says "if morphism=True is passed, then a birational equivalence between F and the Weierstrass curve is returned. If the point happens to be a flex, then this is an isomorphism" and I wasn't thinking.
If I find the flex point on the original cubic is there a way to do this without doing it by hand though? On Saturday, May 24, 2014 12:18:29 PM UTC-4, Volker Braun wrote: > > Its a 4:1 map so you can't invert it... > > On Saturday, May 24, 2014 4:45:11 PM UTC+1, diophan wrote: >> >> Defn: Defined on coordinates by sending (x : y : z) to >> (1/8*x*y - 1/16*y^2 - 1/8*y*z : -x^2 + 1/8*x*y + 3/16*y^2 + x*z >> + 3/8*y*z : -1/256*y^2) >> >> >> -- 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
