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 

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 

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.

Reply via email to