Hi John, To give a bit more weight to the counterargument against the alphabetti solution:
> I agree, and I did not really mean my alphabetti suggestion to be > taken too seriously. In some version, there was an invasive declaration of single character symbols to be symbolic elements. This caused me all sorts of grief when I forgot to declare some variable, I would get an error message far down the line at some completely irrelevant place. I complained and this "feature" was removed (so blame me Chris). For the same reason I voted to leave QQ, RR, and CC, and remove predefinition of Q, R, and C (originally Q == QQ, etc.). If I forget to declare a variable, I want to see it as soon as I try to use it. Since you declare x to be in Qx in your startup file, you don't see the problem, but symbolic variables are viral: if another generator interacts with one it gets the symbolic virus. The current symbolics package supports a lot of features (which wasn't always the case) so maybe the "typical" user won't notice a problem, however this is one instance where one can easily pass over to the symbolics world: sage: P.<X> = PolynomialRing(QQ); sage: X + x X + x sage: f = X^2 - x^2 sage: f.factor() (X - x)*(X + x) sage: f.parent() Symbolic Ring sage: X = f.parent()(X) sage: type(X) <class 'sage.calculus.calculus.SymbolicPolynomial'> sage: type(f.factor()) <class 'sage.calculus.calculus.SymbolicArithmetic'> sage: fac = (1/f).factor() sage: fac == 1/f 1/((X - x)*(X + x)) == 1/(X^2 - x^2) sage: f.is_unit() ... Not implemented error The sorts of questions and functionality one asks the symbolics variables are not the same questions one asks an element of a polynomial ring or of a function field element. Stumbling into this world by mistake because someone predefined a bunch of variables for me was a real headache. SAGE is doing remarkably well at keeping a balance between ease-of- use for beginners and high-end users. --David --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
