Re: [fricas-devel] Factors of multivariate monomials with noncommutative variables

2018-06-05 Thread Raymond Rogers
If anybody is interested: In  A Standard Form in (some) Free Fields: How to construct Minimal Linear Representations Konrad Schrempf 1803.10627.pdf 1) On page 7 "Scalar Multiplication" (first line) my original question is defined/stated.  I will follow up on checking how to access it in the n

Re: [fricas-devel] Factors of multivariate monomials with noncommutative variables

2018-06-01 Thread Bill Page
In principle what you want to do is not that difficult. You need the base field to be something like Expression or maybe Fraction MultivariatePolynomial, etc. , then the noncommutative polynomials are defined over that. What is sometimes a bit tricky is to convince the interpreter that certain symb

Re: [fricas-devel] Factors of multivariate monomials with noncommutative variables

2018-05-29 Thread Raymond Rogers
On 05/29/2018 09:24 AM, Bill Page wrote: On Mon, May 28, 2018 at 9:55 AM, Franz Lehner wrote: On Mon, 28 May 2018, Bill Page wrote: That's a pity. Is the problem with the published algorithm or the source code? Factorization of noncommutative polynomials seems to be a difficult problem. Se

Re: [fricas-devel] Factors of multivariate monomials with noncommutative variables

2018-05-29 Thread Ralf Hemmecke
>> https://arxiv.org/abs/1706.01806 Oho... That paper cites FriCAS directly (obviously for computing a Gröbner basis). Ralf -- You received this message because you are subscribed to the Google Groups "FriCAS - computer algebra system" group. To unsubscribe from this group and stop receiving e

Re: [fricas-devel] Factors of multivariate monomials with noncommutative variables

2018-05-29 Thread Bill Page
On Mon, May 28, 2018 at 9:55 AM, Franz Lehner wrote: > On Mon, 28 May 2018, Bill Page wrote: >> >> That's a pity. Is the problem with the published algorithm or the source >> code? > > Factorization of noncommutative polynomials seems to be a difficult problem. > See > https://arxiv.org/abs/1706.

Re: [fricas-devel] Factors of multivariate monomials with noncommutative variables

2018-05-28 Thread Marduk BP
Hi Kurt > The REDUCE ncpoly is quite slow Perhaps, but it is useful for small expressions and is better than nothing. > Singular's nfactor.lib is quite sophisticated I just came across Singular. Looks pretty good. > This might be a good opportunity for you to write a package ;) I would love t

Re: [fricas-devel] Factors of multivariate monomials with noncommutative variables

2018-05-28 Thread Marduk BP
> That's a pity. Is the problem with the published algorithm or the source code? Fabrizio said there were some bugs in the code. > The terms of XDPOLY consist of the "support" (an element of an > FreeMonoid) and a coefficient. FreeMonoid exports "factors". Thank you Bill! On Mon, May 28, 201

Re: [fricas-devel] Factors of multivariate monomials with noncommutative variables

2018-05-28 Thread Kurt Pagani
Hi Marduk You certainly know that this is not entirely trivial. The REDUCE ncpoly is quite slow (at least it was some years go). IMO Singular's nfactor.lib is quite sophisticated and could also be implemented in fricas (all structures are already availabe, Ring, FreeModule(R,S) is nc ... This migh

Re: [fricas-devel] Factors of multivariate monomials with noncommutative variables

2018-05-28 Thread Franz Lehner
On Mon, 28 May 2018, Bill Page wrote: That's a pity. Is the problem with the published algorithm or the source code? Factorization of noncommutative polynomials seems to be a difficult problem. See https://arxiv.org/abs/1706.01806 for a recent new approach which reduces factorization to the so

Re: [fricas-devel] Factors of multivariate monomials with noncommutative variables

2018-05-28 Thread Bill Page
On Mon, May 28, 2018 at 6:14 AM, Marduk BP wrote: > It turns out that code was never released because it was buggy, so we > can forget about it. > That's a pity. Is the problem with the published algorithm or the source code? > But IMHO what I want to do does not require factoring a polynomial.

Re: [fricas-devel] Factors of multivariate monomials with noncommutative variables

2018-05-28 Thread Marduk BP
It turns out that code was never released because it was buggy, so we can forget about it. But IMHO what I want to do does not require factoring a polynomial. I just want to extract the variables and their exponents from a monomial of noncommutative variables. There must be a (hopefully simple) w

Re: [fricas-devel] Factors of multivariate monomials with noncommutative variables

2018-05-27 Thread Marduk
Thank you Bill! I already contacted the author. I also found out that REDUCE includes this functionality: http://www.reduce-algebra.com/reduce38-docs/ncpoly.pdf I think it should also be included in Axiom/FriCAS. Marduk -- You received this message because you are subscribed to the Google Gr

Re: [fricas-devel] Factors of multivariate monomials with noncommutative variables

2018-05-27 Thread Bill Page
Perhaps this describes what you are looking for: https://arxiv.org/abs/1002.3180 Factorization of Non-Commutative Polynomials Fabrizio Caruso (Submitted on 16 Feb 2010) We describe an algorithm for the factorization of non-commutative polynomials over a field. The first sketch of this algorithm

[fricas-devel] Factors of multivariate monomials with noncommutative variables

2018-05-27 Thread Marduk
Dear all, given a multivariate monomial defined with: poly := MPOLY([x,y], Integer) p : poly := 3*x*y one can obtain the factors of the monomial with factors(p). However, given a multivariate monomial with noncommutative variables defined with: ops := OVAR[A,B] ncomm := XDPOLY(ops, Integer)