Waldek Hebisch <[EMAIL PROTECTED]> writes: | Gabriel Dos Reis wrote: | > "Bill Page" <[EMAIL PROTECTED]> writes: | > | > [...] | > | > | I would like to discuss this more with other active Axiom | > | developers. | > | > Why should InputForm be preferable over Expression T? | > | | When I want use symbolic domain (which is rather rare) I want | a single domain. So one should fix T first.
Of course, you would have to fix T, but I put T there to emphasize that you can fix it to whatever value pleases you. | Natural candidate for T is Integer. But Expression Integer is a field of | characteristic 0. and if you look at what other CASes have been using as symbolic expression, you'll see that most of the time they assume field laws -- with ad-hoc rules when they realize something fishy is going on. | I can easily imagine expresions which go | beyond that (noncommutative variables, zero divisors, mixed | characteristic). Of course, but then you just rediscover many of the problems other CASes run into. Remember, the original issue is how to get an Axiom domain to emulate symbolic computation (as done in other CASes). | Also ATM Expression Integer does not do | zero test before division but IMHO this is a bug. Yes. | OTOH general symbolic domain may lack normal forms. Yes, that is precisely why CASes implement "generalized" polynomials as symbolic expression domains and augment it with ad-hoc rules. -- Gaby _______________________________________________ Axiom-developer mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/axiom-developer
