Ilya Zakharevich on Wed, 10 May 2000 16:52:09 -0400 |
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Re: Domain of elements in PARI |
On Fri, May 05, 2000 at 12:53:40AM +0200, Bill Allombert wrote: > > a) a way to represent an element in a quotient by a non-principal > > ideal in terms of the PARI type system; > > Yes, but we have to add support for rings first, and then add ideals. I do not see a significant need to introduce rings and ideals to PARI. As far as we can mark that operations over a particular element allow the following primes/variables as denominators: 7, 37, y, z, everything is OK. And we can do it today: there are only 15 or some mentions of t_RFRACN in the source. Thus it should be extremly easy to add a new type t_RFRACN_TYPED which works exactly as t_RFRACN, but has an additional GEN. Encode the info about allowed denominators into this GEN. Add a gp constructor for this type. Now one can do calculations with such numbers as before, but one can start to modify the source so that the relevant operations preserve/use this info. Ilya