On Tuesday, June 12, 2018 at 7:24:45 AM UTC-7, Jeroen Demeyer wrote: > > I'd like to say that the following should be coercions: > R -> R[x,y] > R[x] -> R[x,y] > R[y] -> R[x,y] > R[x][y] -> R[x,y] > > But not the following: > R[x,y] -> R[x][y] > R[x,y] -> R[y,x] > R[x,y][z] -> R[x][y,z] >
That looks reasonable to me. Some of the maps in the second list might be conversions? I agree with John that it should at least be possible to create all those maps for sure, and hopefully easily. Possibly a nice test for seeing if the list of coercions and conversions present is sufficient is to see if all those maps can be defined by giving a list of images of generators. Another point to keep in mind: sage: A=PolynomialRing(QQ,["x","y"],order="deglex") sage: B=PolynomialRing(QQ,["x","y"],order="lex") are different rings in sage. What coercions and conversions exist between them? -- 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 https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
