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 +-------------------------------------------------------------+ | Marko Riedel, EDV Neue Arbeit gGmbH, mriedel@lsi.upc.edu | | http://www.geocities.com/markoriedelde/index.html | +-------------------------------------------------------------+