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[Fwd: Re: The specification of sqrfree()]
by Roberto Bagnara 11 Jan '02

11 Jan '02

-------- Original Message -------- Subject: Re: The specification of sqrfree() Date: Wed, 9 Jan 2002 18:21:33 +0100 (CET) From: "Richard B. Kreckel" <kreckel(a)ginac.de> Reply-To: Richard.Kreckel(a)Uni-Mainz.DE To: GiNaC developers list <ginac-devel(a)zino.physik.uni-mainz.de> CC: Roberto Bagnara <bagnara(a)cs.unipr.it> Hi, On Wed, 9 Jan 2002, Roberto Bagnara wrote: [...] > During this work we have found that GiNaC's documentation > is not very precise about what a "square-free factorization" is. Yeah, the defintion given there is not very strict... :-) > Below you find what we believe is a sensible definition > (which also seems to be compatible with the current implementation). > Please, check if that is also consistent with the specification > of GiNaC (we would like to avoid relying on non-features that > may disappear on a subsequent release). > > A polynomial p(X) in Q[X] is said <EM>square-free</EM> > if, whenever two polynomials q(X) and r(X) in Q[X] > are such that p(X) = q(X)^2*r(X), q(X) is constant. I had to read this three times. Do we agree to read `X' ad a n-tuple of symbols? Then I thought this definition does not account of the square-free factorization of p(a,b,c,d) = a*c - b*c - a*d + b*d into (a-b)*(c-d), which is now handled -- this being the change that went into version 1.0.1. But now methinks your definition does indeed cover this. Isn't there a canonical definition for the multivariate case in the literature? And at least over Z[X] and Q[X], you can rely on this extended behaviour. Maple and Mathematica do the same and I need it for my work. If you think it over again with the above case in mind and find that it's okay, a patch for the documentation would be welcome. Regards -richy. -- Richard B. Kreckel <Richard.Kreckel(a)Uni-Mainz.DE> <http://wwwthep.physik.uni-mainz.de/~kreckel/>

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CVS Update: purrs
by Roberto Bagnara 09 Jan '02

09 Jan '02

CVSROOT: /cvs/purrs Module name: purrs Repository: purrs/src/ Changes by: roberto(a)spartacus.cs.unipr.it.(none) 02/01/09 20:23:17 Modified files: purrs/src/: rr_solver.cc Log message: Cleanup started.

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CVS Update: purrs
by Roberto Bagnara 09 Jan '02

09 Jan '02

CVSROOT: /cvs/purrs Module name: purrs Repository: purrs/doc/ Changes by: roberto(a)spartacus.cs.unipr.it.(none) 02/01/09 20:23:01 Modified files: purrs/doc/: devref-browse.doxyconf-latex.in devref-print.doxyconf-latex.in devref.doxyconf-html.in Log message: Document rr_solver.cc, too.

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CVS Update: purrs
by Roberto Bagnara 09 Jan '02

09 Jan '02

CVSROOT: /cvs/purrs Module name: purrs Repository: purrs/doc/ Changes by: roberto(a)spartacus.cs.unipr.it.(none) 02/01/09 20:22:41 Added files: purrs/doc/: purrs.tex Log message: Put under CVS control.

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