On Wed, Jun 3, 2009 at 10:20 AM, Martin Rubey wrote: > > Bill Page writes: >> Note also that >> >> y^2+x >> >> is not syntactically identical to the input >> >> x+y^2 >> >> I wonder why FriCAS changes the order? > > Because the semantics is the same.
Yes, thanks. Now I understand. In the expression: (x+y^2 )::INFORM '(x+y^2 )' is first fully interpreted by Fricas as a polynomial and only then does it coerce (convert?) the result back to InputForm. To do what I expected I guess one could write: (1) -> unparse(parse("x+y^2")$InputForm) (1) "x+y^2" Type: String Then no semantics are involved but if invoke the interpreter explicitly (2) -> unparse(interpret(parse("x+y^2")$InputForm)::INFORM) (2) "y^2+x" Type: String then of course I get the result you showed. > Currently, + is always commutative I think, but compare: > > (18) -> a:XPOLY INT := y*x > > (18) y x 1 > Type: XPolynomial(Integer) > (19) -> b:POLY INT := x*y > > (19) x y > Type: Polynomial(Integer) > > well, embarassingly enough, there is no INFORM for XPOLY :-( > Of course there should be such a coercion. You are right that the result depends on the domain chosen by the interpreter. Regards, Bill Page. _______________________________________________ Axiom-mail mailing list Axiom-mail@nongnu.org http://lists.nongnu.org/mailman/listinfo/axiom-mail