Ralf wrote :
>> In this last case I must be able to recognize the domain :
>> Expression Complex Integer or Expression XXXX Complex YYYYYYY, as
>> Expression Fraction Complex Integer and Expression Complex Fraction
>> Integer or others.
> What does "Expression(X)" actually tell you? Why the X at all?
> Is the imaginary i an element of Expression(Integer)?
This is the question.
I want to code functions for expressions which depend if %i is in the
domain or not.
If I code it in expr.spad I write inside Domain Expression (R) ...
if R has imaginary:()->R and conjugate:()->R
then
expand x ==
a function which separates real and imaginary parts.
exp (1+%i*%pi/7) = exp 1 * (cos (%pi/7) + %i * sin (%pi/7))
else
expand x == expands terms in (nx) to x+x+x+x...+x and a+b
Trigonometric functions are described in the trigcat.spad file.
and expand/rewrite/combine are related to theses functions,
So [a part of] the code might be in this category trigcat.spad.
but in this category I can't get any information about type of x in sin x.
The paradox is : trigonometric transforms can't be code in the category
trigcat.
Methods of expand/rewrite/combine are free of representation, but
must(?) be code in the domain Expression not in the category.
I hope I can explain what perplexity I feel in this example.
F.
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