Let f be a polynomial in two variables x and y over a ring R. Consider the following three commands
i) f(2,3) ii) f(x=2,y=3) iii) f.subs(x=2,y=3) They give the same results but not the same type. i) gives an element in R while ii) and iii) are constant polynomials in two variables. Follinwg the documentation, i) and ii) should give an element in R while iii) is a polynomial. So something should be changed. The question is what. I would expect all three to give back elements of R. This is maybe a slightly non- canonical choice given that f(x=3) does not (and should not) give back a polynomial in one variable or an element in the quotient ring R[x,y]/ (x-3). But still I think that is what a naive user like me would expect when evaluating all variables. Note that for a polynomial in one variable all three are elements in R. The changes for i) in a __call__ of sage.rings.polynomial.multi_polynomial_libsingular.pyx were introduced in ticket #8502. I came across this issue in #10888. I propose to change at least so that ii), which is the __call__ method, does the same as i) - see attached patch. But the question is if one wants to change subs(). I figured that some people in this list may have an opinion on this. Chris. -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
