Re: [Axiom-developer] CAS for the masses

[Ondrej Certik]

> The usual example is:
>
>   (1/2)*x^2 + (1/3)*x + 3
>                             Type: Polynomial Fraction Integer
>
> %::Fraction(Polynomial(Integer))
>
>       2
>     3x  + 2x + 18
>     -------------
>           6
>                             Type: Fraction Polynomial Integer
>
>
> When you read a maths book most of the equations are actually just
> "icons". The real meaning of the equation is in the surrounding text
> and context. Axiom carries that surrounding information in the type
> whereas other systems focus on the "icons" and syntactic manipulations.


I have this question:

The above expressions can be assembled just from these 4 types (or
classes in SymPy): Add, Mul, Pow, Integer

what is the advantage to introduce more classes, like Polynomial
Fraction Integer or Fraction Polynomial Integer?

Because having the expression in the form of the 4 basic classes (Add,
Mul, Pow, Integer), everything else can be easily inferred from this.

Ondrej