Consider the following: sage: R.<x,y> = QQ[] ....: p = x + y ....: print(parent(p.subs(x=1))) ....: print(parent(p.subs(x=1, y=2))) ....: print(parent(p(x=1))) ....: print(parent(p(x=1, y=2))) ....: print(parent(p(1, 2))) ....: print() ....: R.<x,y> = QQ["a"][] ....: p = x + y ....: print(parent(p.subs(x=1))) ....: print(parent(p.subs(x=1, y=2))) ....: print(parent(p(x=1))) ....: print(parent(p(x=1, y=2))) ....: print(parent(p(1, 2))) Multivariate Polynomial Ring in x, y over Rational Field Multivariate Polynomial Ring in x, y over Rational Field Multivariate Polynomial Ring in x, y over Rational Field Multivariate Polynomial Ring in x, y over Rational Field Rational Field
Multivariate Polynomial Ring in x, y over Univariate Polynomial Ring in a over Rational Field Univariate Polynomial Ring in a over Rational Field Multivariate Polynomial Ring in x, y over Univariate Polynomial Ring in a over Rational Field Univariate Polynomial Ring in a over Rational Field Univariate Polynomial Ring in a over Rational Field It seems to me that when a tuple of values is provided for all variables, the result is expected to be the polynomial evaluation and should live in the base ring. But if named substitutions are used, the result is going to be a polynomial of the same ring, even if it happens to be a constant for some reason. If that is not the case, one has to write different code to treat evaluations. So I'd say that the first ring here behaves well and the second one does not. What do you think? Thank you! Andrey -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/70ebd34f-0748-4472-a4db-d538fc896a96n%40googlegroups.com.
