[GiNaC-list] hash tables and sets

[Marko Riedel]

Hi folks, 
 
I would like to write a set implementation for expressions, or borrow 
one, if it has already been written. 
 
I have several questions. 

1. What C++ type is best suited to representing sets?

2. Is there a hash function implemented for GiNaC expressions?

3. Can GiNaC expressions be put into some kind of canonical form?

4. (Requirement.) The hash function should be such that e.g.

   a + b + c * (d + e)

and

   b + (e + d) * c + a

hash to the same value.

Thanks!

Marko Riedel

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